diff --git a/protos/google/cloud/documentai/v1/document.proto b/protos/google/cloud/documentai/v1/document.proto
index 467a44921..e6368bad5 100644
--- a/protos/google/cloud/documentai/v1/document.proto
+++ b/protos/google/cloud/documentai/v1/document.proto
@@ -1,4 +1,4 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@ syntax = "proto3";
 
 package google.cloud.documentai.v1;
 
+import "google/api/annotations.proto";
 import "google/api/field_behavior.proto";
 import "google/cloud/documentai/v1/geometry.proto";
 import "google/protobuf/timestamp.proto";
@@ -25,7 +26,6 @@ import "google/type/date.proto";
 import "google/type/datetime.proto";
 import "google/type/money.proto";
 import "google/type/postal_address.proto";
-import "google/api/annotations.proto";
 
 option csharp_namespace = "Google.Cloud.DocumentAI.V1";
 option go_package = "google.golang.org/genproto/googleapis/cloud/documentai/v1;documentai";
@@ -51,7 +51,8 @@ message Document {
     // Total number of shards.
     int64 shard_count = 2;
 
-    // The index of the first character in [Document.text][google.cloud.documentai.v1.Document.text] in the overall
+    // The index of the first character in
+    // [Document.text][google.cloud.documentai.v1.Document.text] in the overall
     // document global text.
     int64 text_offset = 3;
   }
@@ -68,7 +69,8 @@ message Document {
       string unit = 2;
     }
 
-    // Text anchor indexing into the [Document.text][google.cloud.documentai.v1.Document.text].
+    // Text anchor indexing into the
+    // [Document.text][google.cloud.documentai.v1.Document.text].
     TextAnchor text_anchor = 1;
 
     // Text color.
@@ -165,25 +167,31 @@ message Document {
         PAGE_LEFT = 4;
       }
 
-      // Text anchor indexing into the [Document.text][google.cloud.documentai.v1.Document.text].
+      // Text anchor indexing into the
+      // [Document.text][google.cloud.documentai.v1.Document.text].
       TextAnchor text_anchor = 1;
 
-      // Confidence of the current [Layout][google.cloud.documentai.v1.Document.Page.Layout] within context of the object this
-      // layout is for. e.g. confidence can be for a single token, a table,
-      // a visual element, etc. depending on context. Range [0, 1].
+      // Confidence of the current
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] within
+      // context of the object this layout is for. e.g. confidence can be for a
+      // single token, a table, a visual element, etc. depending on context.
+      // Range [0, 1].
       float confidence = 2;
 
-      // The bounding polygon for the [Layout][google.cloud.documentai.v1.Document.Page.Layout].
+      // The bounding polygon for the
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout].
       BoundingPoly bounding_poly = 3;
 
-      // Detected orientation for the [Layout][google.cloud.documentai.v1.Document.Page.Layout].
+      // Detected orientation for the
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout].
       Orientation orientation = 4;
     }
 
     // A block has a set of lines (collected into paragraphs) that have a
     // common line-spacing and orientation.
     message Block {
-      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Block][google.cloud.documentai.v1.Document.Page.Block].
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for
+      // [Block][google.cloud.documentai.v1.Document.Page.Block].
       Layout layout = 1;
 
       // A list of detected languages together with confidence.
@@ -195,7 +203,8 @@ message Document {
 
     // A collection of lines that a human would perceive as a paragraph.
     message Paragraph {
-      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Paragraph][google.cloud.documentai.v1.Document.Page.Paragraph].
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for
+      // [Paragraph][google.cloud.documentai.v1.Document.Page.Paragraph].
       Layout layout = 1;
 
       // A list of detected languages together with confidence.
@@ -208,7 +217,8 @@ message Document {
     // A collection of tokens that a human would perceive as a line.
     // Does not cross column boundaries, can be horizontal, vertical, etc.
     message Line {
-      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Line][google.cloud.documentai.v1.Document.Page.Line].
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for
+      // [Line][google.cloud.documentai.v1.Document.Page.Line].
       Layout layout = 1;
 
       // A list of detected languages together with confidence.
@@ -220,7 +230,8 @@ message Document {
 
     // A detected token.
     message Token {
-      // Detected break at the end of a [Token][google.cloud.documentai.v1.Document.Page.Token].
+      // Detected break at the end of a
+      // [Token][google.cloud.documentai.v1.Document.Page.Token].
       message DetectedBreak {
         // Enum to denote the type of break found.
         enum Type {
@@ -241,10 +252,12 @@ message Document {
         Type type = 1;
       }
 
-      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Token][google.cloud.documentai.v1.Document.Page.Token].
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for
+      // [Token][google.cloud.documentai.v1.Document.Page.Token].
       Layout layout = 1;
 
-      // Detected break at the end of a [Token][google.cloud.documentai.v1.Document.Page.Token].
+      // Detected break at the end of a
+      // [Token][google.cloud.documentai.v1.Document.Page.Token].
       DetectedBreak detected_break = 2;
 
       // A list of detected languages together with confidence.
@@ -254,13 +267,25 @@ message Document {
       Provenance provenance = 4;
     }
 
+    // A detected symbol.
+    message Symbol {
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for
+      // [Symbol][google.cloud.documentai.v1.Document.Page.Symbol].
+      Layout layout = 1;
+
+      // A list of detected languages together with confidence.
+      repeated DetectedLanguage detected_languages = 2;
+    }
+
     // Detected non-text visual elements e.g. checkbox, signature etc. on the
     // page.
     message VisualElement {
-      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [VisualElement][google.cloud.documentai.v1.Document.Page.VisualElement].
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for
+      // [VisualElement][google.cloud.documentai.v1.Document.Page.VisualElement].
       Layout layout = 1;
 
-      // Type of the [VisualElement][google.cloud.documentai.v1.Document.Page.VisualElement].
+      // Type of the
+      // [VisualElement][google.cloud.documentai.v1.Document.Page.VisualElement].
       string type = 2;
 
       // A list of detected languages together with confidence.
@@ -277,7 +302,8 @@ message Document {
 
       // A cell representation inside the table.
       message TableCell {
-        // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [TableCell][google.cloud.documentai.v1.Document.Page.Table.TableCell].
+        // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for
+        // [TableCell][google.cloud.documentai.v1.Document.Page.Table.TableCell].
         Layout layout = 1;
 
         // How many rows this cell spans.
@@ -290,7 +316,8 @@ message Document {
         repeated DetectedLanguage detected_languages = 4;
       }
 
-      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for [Table][google.cloud.documentai.v1.Document.Page.Table].
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for
+      // [Table][google.cloud.documentai.v1.Document.Page.Table].
       Layout layout = 1;
 
       // Header rows of the table.
@@ -305,11 +332,13 @@ message Document {
 
     // A form field detected on the page.
     message FormField {
-      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for the [FormField][google.cloud.documentai.v1.Document.Page.FormField] name. e.g. `Address`, `Email`,
-      // `Grand total`, `Phone number`, etc.
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for the
+      // [FormField][google.cloud.documentai.v1.Document.Page.FormField] name.
+      // e.g. `Address`, `Email`, `Grand total`, `Phone number`, etc.
       Layout field_name = 1;
 
-      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for the [FormField][google.cloud.documentai.v1.Document.Page.FormField] value.
+      // [Layout][google.cloud.documentai.v1.Document.Page.Layout] for the
+      // [FormField][google.cloud.documentai.v1.Document.Page.FormField] value.
       Layout field_value = 2;
 
       // A list of detected languages for name together with confidence.
@@ -333,16 +362,18 @@ message Document {
     message DetectedLanguage {
       // The BCP-47 language code, such as "en-US" or "sr-Latn". For more
       // information, see
-      // http://www.unicode.org/reports/tr35/#Unicode_locale_identifier.
+      // https://www.unicode.org/reports/tr35/#Unicode_locale_identifier.
       string language_code = 1;
 
       // Confidence of detected language. Range [0, 1].
       float confidence = 2;
     }
 
-    // 1-based index for current [Page][google.cloud.documentai.v1.Document.Page] in a parent [Document][google.cloud.documentai.v1.Document].
-    // Useful when a page is taken out of a [Document][google.cloud.documentai.v1.Document] for individual
-    // processing.
+    // 1-based index for current
+    // [Page][google.cloud.documentai.v1.Document.Page] in a parent
+    // [Document][google.cloud.documentai.v1.Document]. Useful when a page is
+    // taken out of a [Document][google.cloud.documentai.v1.Document] for
+    // individual processing.
     int32 page_number = 1;
 
     // Rendered image for this page. This image is preprocessed to remove any
@@ -389,17 +420,23 @@ message Document {
     // A list of visually detected form fields on the page.
     repeated FormField form_fields = 11;
 
+    // A list of visually detected symbols on the page.
+    repeated Symbol symbols = 12;
+
     // The history of this page.
     Provenance provenance = 16;
   }
 
-  // A phrase in the text that is a known entity type, such as a person, an
-  // organization, or location.
+  // An entity that could be a phrase in the text or a property that belongs to
+  // the document. It is a known entity type, such as a person, an organization,
+  // or location.
   message Entity {
     // Parsed and normalized entity value.
     message NormalizedValue {
-      // Structured entity value. Must match entity type defined in schema if
-      // known. If this field is present, the 'text' field is still populated.
+      // An optional structured entity value.
+      // Must match entity type defined in schema if
+      // known. If this field is present, the `text` field could also be
+      // populated.
       oneof structured_value {
         // Money value. See also:
         // https://github.com/googleapis/googleapis/blob/master/google/type/money.proto
@@ -422,24 +459,29 @@ message Document {
         bool boolean_value = 6;
       }
 
-      // Required. Normalized entity value stored as a string. This field is populated for
-      // supported document type (e.g. Invoice). For some entity types, one of
-      // respective 'structured_value' fields may also be populated.
+      // Optional. An optional field to store a normalized string.
+      // For some entity types, one of respective `structured_value` fields may
+      // also be populated. Also not all the types of `structured_value` will be
+      // normalized. For example, some processors may not generate float
+      // or int normalized text by default.
       //
+      // Below are sample formats mapped to structured values.
       // - Money/Currency type (`money_value`) is in the ISO 4217 text format.
       // - Date type (`date_value`) is in the ISO 8601 text format.
       // - Datetime type (`datetime_value`) is in the ISO 8601 text format.
-      string text = 1 [(google.api.field_behavior) = REQUIRED];
+      string text = 1 [(google.api.field_behavior) = OPTIONAL];
     }
 
     // Optional. Provenance of the entity.
-    // Text anchor indexing into the [Document.text][google.cloud.documentai.v1.Document.text].
+    // Text anchor indexing into the
+    // [Document.text][google.cloud.documentai.v1.Document.text].
     TextAnchor text_anchor = 1 [(google.api.field_behavior) = OPTIONAL];
 
     // Entity type from a schema e.g. `Address`.
     string type = 2;
 
-    // Optional. Text value in the document e.g. `1600 Amphitheatre Pkwy`.
+    // Optional. Text value in the document e.g. `1600 Amphitheatre Pkwy`. If
+    // the entity is not present in the document, this field will be empty.
     string mention_text = 3 [(google.api.field_behavior) = OPTIONAL];
 
     // Optional. Deprecated.  Use `id` field instead.
@@ -448,32 +490,35 @@ message Document {
     // Optional. Confidence of detected Schema entity. Range [0, 1].
     float confidence = 5 [(google.api.field_behavior) = OPTIONAL];
 
-    // Optional. Represents the provenance of this entity wrt. the location on the
-    // page where it was found.
+    // Optional. Represents the provenance of this entity wrt. the location on
+    // the page where it was found.
     PageAnchor page_anchor = 6 [(google.api.field_behavior) = OPTIONAL];
 
     // Optional. Canonical id. This will be a unique value in the entity list
     // for this document.
     string id = 7 [(google.api.field_behavior) = OPTIONAL];
 
-    // Optional. Normalized entity value. Absent if the extracted value could not be
-    // converted or the type (e.g. address) is not supported for certain
+    // Optional. Normalized entity value. Absent if the extracted value could
+    // not be converted or the type (e.g. address) is not supported for certain
     // parsers. This field is also only populated for certain supported document
     // types.
-    NormalizedValue normalized_value = 9 [(google.api.field_behavior) = OPTIONAL];
+    NormalizedValue normalized_value = 9
+        [(google.api.field_behavior) = OPTIONAL];
 
-    // Optional. Entities can be nested to form a hierarchical data structure representing
-    // the content in the document.
+    // Optional. Entities can be nested to form a hierarchical data structure
+    // representing the content in the document.
     repeated Entity properties = 10 [(google.api.field_behavior) = OPTIONAL];
 
     // Optional. The history of this annotation.
     Provenance provenance = 11 [(google.api.field_behavior) = OPTIONAL];
 
-    // Optional. Whether the entity will be redacted for de-identification purposes.
+    // Optional. Whether the entity will be redacted for de-identification
+    // purposes.
     bool redacted = 12 [(google.api.field_behavior) = OPTIONAL];
   }
 
-  // Relationship between [Entities][google.cloud.documentai.v1.Document.Entity].
+  // Relationship between
+  // [Entities][google.cloud.documentai.v1.Document.Entity].
   message EntityRelation {
     // Subject entity id.
     string subject_id = 1;
@@ -485,31 +530,40 @@ message Document {
     string relation = 3;
   }
 
-  // Text reference indexing into the [Document.text][google.cloud.documentai.v1.Document.text].
+  // Text reference indexing into the
+  // [Document.text][google.cloud.documentai.v1.Document.text].
   message TextAnchor {
-    // A text segment in the [Document.text][google.cloud.documentai.v1.Document.text]. The indices may be out of bounds
-    // which indicate that the text extends into another document shard for
-    // large sharded documents. See [ShardInfo.text_offset][google.cloud.documentai.v1.Document.ShardInfo.text_offset]
+    // A text segment in the
+    // [Document.text][google.cloud.documentai.v1.Document.text]. The indices
+    // may be out of bounds which indicate that the text extends into another
+    // document shard for large sharded documents. See
+    // [ShardInfo.text_offset][google.cloud.documentai.v1.Document.ShardInfo.text_offset]
     message TextSegment {
-      // [TextSegment][google.cloud.documentai.v1.Document.TextAnchor.TextSegment] start UTF-8 char index in the [Document.text][google.cloud.documentai.v1.Document.text].
+      // [TextSegment][google.cloud.documentai.v1.Document.TextAnchor.TextSegment]
+      // start UTF-8 char index in the
+      // [Document.text][google.cloud.documentai.v1.Document.text].
       int64 start_index = 1;
 
-      // [TextSegment][google.cloud.documentai.v1.Document.TextAnchor.TextSegment] half open end UTF-8 char index in the
+      // [TextSegment][google.cloud.documentai.v1.Document.TextAnchor.TextSegment]
+      // half open end UTF-8 char index in the
       // [Document.text][google.cloud.documentai.v1.Document.text].
       int64 end_index = 2;
     }
 
-    // The text segments from the [Document.text][google.cloud.documentai.v1.Document.text].
+    // The text segments from the
+    // [Document.text][google.cloud.documentai.v1.Document.text].
     repeated TextSegment text_segments = 1;
 
     // Contains the content of the text span so that users do
-    // not have to look it up in the text_segments.
+    // not have to look it up in the text_segments.  It is always
+    // populated for formFields.
     string content = 2;
   }
 
-  // Referencing the visual context of the entity in the [Document.pages][google.cloud.documentai.v1.Document.pages].
-  // Page anchors can be cross-page, consist of multiple bounding polygons and
-  // optionally reference specific layout element types.
+  // Referencing the visual context of the entity in the
+  // [Document.pages][google.cloud.documentai.v1.Document.pages]. Page anchors
+  // can be cross-page, consist of multiple bounding polygons and optionally
+  // reference specific layout element types.
   message PageAnchor {
     // Represents a weak reference to a page element within a document.
     message PageRef {
@@ -518,47 +572,65 @@ message Document {
         // Layout Unspecified.
         LAYOUT_TYPE_UNSPECIFIED = 0;
 
-        // References a [Page.blocks][google.cloud.documentai.v1.Document.Page.blocks] element.
+        // References a
+        // [Page.blocks][google.cloud.documentai.v1.Document.Page.blocks]
+        // element.
         BLOCK = 1;
 
-        // References a [Page.paragraphs][google.cloud.documentai.v1.Document.Page.paragraphs] element.
+        // References a
+        // [Page.paragraphs][google.cloud.documentai.v1.Document.Page.paragraphs]
+        // element.
         PARAGRAPH = 2;
 
-        // References a [Page.lines][google.cloud.documentai.v1.Document.Page.lines] element.
+        // References a
+        // [Page.lines][google.cloud.documentai.v1.Document.Page.lines] element.
         LINE = 3;
 
-        // References a [Page.tokens][google.cloud.documentai.v1.Document.Page.tokens] element.
+        // References a
+        // [Page.tokens][google.cloud.documentai.v1.Document.Page.tokens]
+        // element.
         TOKEN = 4;
 
-        // References a [Page.visual_elements][google.cloud.documentai.v1.Document.Page.visual_elements] element.
+        // References a
+        // [Page.visual_elements][google.cloud.documentai.v1.Document.Page.visual_elements]
+        // element.
         VISUAL_ELEMENT = 5;
 
-        // Refrrences a [Page.tables][google.cloud.documentai.v1.Document.Page.tables] element.
+        // Refrrences a
+        // [Page.tables][google.cloud.documentai.v1.Document.Page.tables]
+        // element.
         TABLE = 6;
 
-        // References a [Page.form_fields][google.cloud.documentai.v1.Document.Page.form_fields] element.
+        // References a
+        // [Page.form_fields][google.cloud.documentai.v1.Document.Page.form_fields]
+        // element.
         FORM_FIELD = 7;
       }
 
-      // Required. Index into the [Document.pages][google.cloud.documentai.v1.Document.pages] element, for example using
-      // [Document.pages][page_refs.page] to locate the related page element.
-      // This field is skipped when its value is the default 0. See
+      // Required. Index into the
+      // [Document.pages][google.cloud.documentai.v1.Document.pages] element,
+      // for example using [Document.pages][page_refs.page] to locate the
+      // related page element. This field is skipped when its value is the
+      // default 0. See
       // https://developers.google.com/protocol-buffers/docs/proto3#json.
       int64 page = 1 [(google.api.field_behavior) = REQUIRED];
 
-      // Optional. The type of the layout element that is being referenced if any.
+      // Optional. The type of the layout element that is being referenced if
+      // any.
       LayoutType layout_type = 2 [(google.api.field_behavior) = OPTIONAL];
 
-      // Optional. Deprecated.  Use [PageRef.bounding_poly][google.cloud.documentai.v1.Document.PageAnchor.PageRef.bounding_poly] instead.
-      string layout_id = 3 [
-        deprecated = true,
-        (google.api.field_behavior) = OPTIONAL
-      ];
+      // Optional. Deprecated.  Use
+      // [PageRef.bounding_poly][google.cloud.documentai.v1.Document.PageAnchor.PageRef.bounding_poly]
+      // instead.
+      string layout_id = 3
+          [deprecated = true, (google.api.field_behavior) = OPTIONAL];
 
-      // Optional. Identifies the bounding polygon of a layout element on the page.
+      // Optional. Identifies the bounding polygon of a layout element on the
+      // page.
       BoundingPoly bounding_poly = 4 [(google.api.field_behavior) = OPTIONAL];
 
-      // Optional. Confidence of detected page element, if applicable. Range [0, 1].
+      // Optional. Confidence of detected page element, if applicable. Range [0,
+      // 1].
       float confidence = 5 [(google.api.field_behavior) = OPTIONAL];
     }
 
@@ -569,15 +641,14 @@ message Document {
   // Structure to identify provenance relationships between annotations in
   // different revisions.
   message Provenance {
-    // Structure for referencing parent provenances.  When an element replaces
-    // one of more other elements parent references identify the elements that
-    // are replaced.
+    // The parent element the current element is based on. Used for
+    // referencing/aligning, removal and replacement operations.
     message Parent {
-      // The index of the [Document.revisions] identifying the parent revision.
+      // The index of the index into current revision's parent_ids list.
       int32 revision = 1;
 
-      // The index of the parent revisions corresponding collection of items
-      // (eg. list of entities, properties within entities, etc.)
+      // The index of the parent item in the corresponding item list (eg. list
+      // of entities, properties within entities, etc.) in the parent revision.
       int32 index = 3;
 
       // The id of the parent provenance.
@@ -586,19 +657,20 @@ message Document {
 
     // If a processor or agent does an explicit operation on existing elements.
     enum OperationType {
-      // Operation type unspecified.
+      // Operation type unspecified. If no operation is specified a provenance
+      // entry is simply used to match against a `parent`.
       OPERATION_TYPE_UNSPECIFIED = 0;
 
-      // Add an element.  Implicit if no `parents` are set for the provenance.
+      // Add an element.
       ADD = 1;
 
-      // The element is removed.  No `parents` should be set.
+      // Remove an element identified by `parent`.
       REMOVE = 2;
 
-      // Explicitly replaces the element(s) identified by `parents`.
+      // Replace an element identified by `parent`.
       REPLACE = 3;
 
-      // Element is requested for human review.
+      // Request human review for the element identified by `parent`.
       EVAL_REQUESTED = 4;
 
       // Element is reviewed and approved at human review, confidence will be
@@ -664,8 +736,9 @@ message Document {
   // This message is used for text changes aka. OCR corrections.
   message TextChange {
     // Provenance of the correction.
-    // Text anchor indexing into the [Document.text][google.cloud.documentai.v1.Document.text].  There can only be a
-    // single `TextAnchor.text_segments` element.  If the start and
+    // Text anchor indexing into the
+    // [Document.text][google.cloud.documentai.v1.Document.text].  There can
+    // only be a single `TextAnchor.text_segments` element.  If the start and
     // end index of the text segment are the same, the text change is inserted
     // before that index.
     TextAnchor text_anchor = 1;
@@ -706,11 +779,13 @@ message Document {
   // Visual page layout for the [Document][google.cloud.documentai.v1.Document].
   repeated Page pages = 6;
 
-  // A list of entities detected on [Document.text][google.cloud.documentai.v1.Document.text]. For document shards,
-  // entities in this list may cross shard boundaries.
+  // A list of entities detected on
+  // [Document.text][google.cloud.documentai.v1.Document.text]. For document
+  // shards, entities in this list may cross shard boundaries.
   repeated Entity entities = 7;
 
-  // Relationship among [Document.entities][google.cloud.documentai.v1.Document.entities].
+  // Relationship among
+  // [Document.entities][google.cloud.documentai.v1.Document.entities].
   repeated EntityRelation entity_relations = 8;
 
   // A list of text corrections made to [Document.text].  This is usually
diff --git a/protos/google/cloud/documentai/v1beta3/document.proto b/protos/google/cloud/documentai/v1beta3/document.proto
index abba3ae19..760cd5115 100644
--- a/protos/google/cloud/documentai/v1beta3/document.proto
+++ b/protos/google/cloud/documentai/v1beta3/document.proto
@@ -1,4 +1,4 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -16,6 +16,7 @@ syntax = "proto3";
 
 package google.cloud.documentai.v1beta3;
 
+import "google/api/annotations.proto";
 import "google/api/field_behavior.proto";
 import "google/cloud/documentai/v1beta3/geometry.proto";
 import "google/protobuf/timestamp.proto";
@@ -25,7 +26,6 @@ import "google/type/date.proto";
 import "google/type/datetime.proto";
 import "google/type/money.proto";
 import "google/type/postal_address.proto";
-import "google/api/annotations.proto";
 
 option csharp_namespace = "Google.Cloud.DocumentAI.V1Beta3";
 option go_package = "google.golang.org/genproto/googleapis/cloud/documentai/v1beta3;documentai";
@@ -51,8 +51,9 @@ message Document {
     // Total number of shards.
     int64 shard_count = 2;
 
-    // The index of the first character in [Document.text][google.cloud.documentai.v1beta3.Document.text] in the overall
-    // document global text.
+    // The index of the first character in
+    // [Document.text][google.cloud.documentai.v1beta3.Document.text] in the
+    // overall document global text.
     int64 text_offset = 3;
   }
 
@@ -68,7 +69,8 @@ message Document {
       string unit = 2;
     }
 
-    // Text anchor indexing into the [Document.text][google.cloud.documentai.v1beta3.Document.text].
+    // Text anchor indexing into the
+    // [Document.text][google.cloud.documentai.v1beta3.Document.text].
     TextAnchor text_anchor = 1;
 
     // Text color.
@@ -165,25 +167,31 @@ message Document {
         PAGE_LEFT = 4;
       }
 
-      // Text anchor indexing into the [Document.text][google.cloud.documentai.v1beta3.Document.text].
+      // Text anchor indexing into the
+      // [Document.text][google.cloud.documentai.v1beta3.Document.text].
       TextAnchor text_anchor = 1;
 
-      // Confidence of the current [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] within context of the object this
-      // layout is for. e.g. confidence can be for a single token, a table,
-      // a visual element, etc. depending on context. Range [0, 1].
+      // Confidence of the current
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] within
+      // context of the object this layout is for. e.g. confidence can be for a
+      // single token, a table, a visual element, etc. depending on context.
+      // Range [0, 1].
       float confidence = 2;
 
-      // The bounding polygon for the [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout].
+      // The bounding polygon for the
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout].
       BoundingPoly bounding_poly = 3;
 
-      // Detected orientation for the [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout].
+      // Detected orientation for the
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout].
       Orientation orientation = 4;
     }
 
     // A block has a set of lines (collected into paragraphs) that have a
     // common line-spacing and orientation.
     message Block {
-      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for [Block][google.cloud.documentai.v1beta3.Document.Page.Block].
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for
+      // [Block][google.cloud.documentai.v1beta3.Document.Page.Block].
       Layout layout = 1;
 
       // A list of detected languages together with confidence.
@@ -195,7 +203,8 @@ message Document {
 
     // A collection of lines that a human would perceive as a paragraph.
     message Paragraph {
-      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for [Paragraph][google.cloud.documentai.v1beta3.Document.Page.Paragraph].
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for
+      // [Paragraph][google.cloud.documentai.v1beta3.Document.Page.Paragraph].
       Layout layout = 1;
 
       // A list of detected languages together with confidence.
@@ -208,7 +217,8 @@ message Document {
     // A collection of tokens that a human would perceive as a line.
     // Does not cross column boundaries, can be horizontal, vertical, etc.
     message Line {
-      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for [Line][google.cloud.documentai.v1beta3.Document.Page.Line].
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for
+      // [Line][google.cloud.documentai.v1beta3.Document.Page.Line].
       Layout layout = 1;
 
       // A list of detected languages together with confidence.
@@ -220,7 +230,8 @@ message Document {
 
     // A detected token.
     message Token {
-      // Detected break at the end of a [Token][google.cloud.documentai.v1beta3.Document.Page.Token].
+      // Detected break at the end of a
+      // [Token][google.cloud.documentai.v1beta3.Document.Page.Token].
       message DetectedBreak {
         // Enum to denote the type of break found.
         enum Type {
@@ -241,10 +252,12 @@ message Document {
         Type type = 1;
       }
 
-      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for [Token][google.cloud.documentai.v1beta3.Document.Page.Token].
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for
+      // [Token][google.cloud.documentai.v1beta3.Document.Page.Token].
       Layout layout = 1;
 
-      // Detected break at the end of a [Token][google.cloud.documentai.v1beta3.Document.Page.Token].
+      // Detected break at the end of a
+      // [Token][google.cloud.documentai.v1beta3.Document.Page.Token].
       DetectedBreak detected_break = 2;
 
       // A list of detected languages together with confidence.
@@ -254,13 +267,25 @@ message Document {
       Provenance provenance = 4;
     }
 
+    // A detected symbol.
+    message Symbol {
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for
+      // [Symbol][google.cloud.documentai.v1beta3.Document.Page.Symbol].
+      Layout layout = 1;
+
+      // A list of detected languages together with confidence.
+      repeated DetectedLanguage detected_languages = 2;
+    }
+
     // Detected non-text visual elements e.g. checkbox, signature etc. on the
     // page.
     message VisualElement {
-      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for [VisualElement][google.cloud.documentai.v1beta3.Document.Page.VisualElement].
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for
+      // [VisualElement][google.cloud.documentai.v1beta3.Document.Page.VisualElement].
       Layout layout = 1;
 
-      // Type of the [VisualElement][google.cloud.documentai.v1beta3.Document.Page.VisualElement].
+      // Type of the
+      // [VisualElement][google.cloud.documentai.v1beta3.Document.Page.VisualElement].
       string type = 2;
 
       // A list of detected languages together with confidence.
@@ -277,7 +302,8 @@ message Document {
 
       // A cell representation inside the table.
       message TableCell {
-        // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for [TableCell][google.cloud.documentai.v1beta3.Document.Page.Table.TableCell].
+        // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for
+        // [TableCell][google.cloud.documentai.v1beta3.Document.Page.Table.TableCell].
         Layout layout = 1;
 
         // How many rows this cell spans.
@@ -290,7 +316,8 @@ message Document {
         repeated DetectedLanguage detected_languages = 4;
       }
 
-      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for [Table][google.cloud.documentai.v1beta3.Document.Page.Table].
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for
+      // [Table][google.cloud.documentai.v1beta3.Document.Page.Table].
       Layout layout = 1;
 
       // Header rows of the table.
@@ -305,11 +332,14 @@ message Document {
 
     // A form field detected on the page.
     message FormField {
-      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for the [FormField][google.cloud.documentai.v1beta3.Document.Page.FormField] name. e.g. `Address`, `Email`,
-      // `Grand total`, `Phone number`, etc.
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for the
+      // [FormField][google.cloud.documentai.v1beta3.Document.Page.FormField]
+      // name. e.g. `Address`, `Email`, `Grand total`, `Phone number`, etc.
       Layout field_name = 1;
 
-      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for the [FormField][google.cloud.documentai.v1beta3.Document.Page.FormField] value.
+      // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for the
+      // [FormField][google.cloud.documentai.v1beta3.Document.Page.FormField]
+      // value.
       Layout field_value = 2;
 
       // A list of detected languages for name together with confidence.
@@ -333,16 +363,18 @@ message Document {
     message DetectedLanguage {
       // The BCP-47 language code, such as "en-US" or "sr-Latn". For more
       // information, see
-      // http://www.unicode.org/reports/tr35/#Unicode_locale_identifier.
+      // https://www.unicode.org/reports/tr35/#Unicode_locale_identifier.
       string language_code = 1;
 
       // Confidence of detected language. Range [0, 1].
       float confidence = 2;
     }
 
-    // 1-based index for current [Page][google.cloud.documentai.v1beta3.Document.Page] in a parent [Document][google.cloud.documentai.v1beta3.Document].
-    // Useful when a page is taken out of a [Document][google.cloud.documentai.v1beta3.Document] for individual
-    // processing.
+    // 1-based index for current
+    // [Page][google.cloud.documentai.v1beta3.Document.Page] in a parent
+    // [Document][google.cloud.documentai.v1beta3.Document]. Useful when a page
+    // is taken out of a [Document][google.cloud.documentai.v1beta3.Document]
+    // for individual processing.
     int32 page_number = 1;
 
     // Rendered image for this page. This image is preprocessed to remove any
@@ -351,13 +383,15 @@ message Document {
     Image image = 13;
 
     // Transformation matrices that were applied to the original document image
-    // to produce [Page.image][google.cloud.documentai.v1beta3.Document.Page.image].
+    // to produce
+    // [Page.image][google.cloud.documentai.v1beta3.Document.Page.image].
     repeated Matrix transforms = 14;
 
     // Physical dimension of the page.
     Dimension dimension = 2;
 
-    // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for the page.
+    // [Layout][google.cloud.documentai.v1beta3.Document.Page.Layout] for the
+    // page.
     Layout layout = 3;
 
     // A list of detected languages together with confidence.
@@ -389,17 +423,23 @@ message Document {
     // A list of visually detected form fields on the page.
     repeated FormField form_fields = 11;
 
+    // A list of visually detected symbols on the page.
+    repeated Symbol symbols = 12;
+
     // The history of this page.
     Provenance provenance = 16;
   }
 
-  // A phrase in the text that is a known entity type, such as a person, an
-  // organization, or location.
+  // An entity that could be a phrase in the text or a property that belongs to
+  // the document. It is a known entity type, such as a person, an organization,
+  // or location.
   message Entity {
     // Parsed and normalized entity value.
     message NormalizedValue {
-      // Structured entity value. Must match entity type defined in schema if
-      // known. If this field is present, the 'text' field is still populated.
+      // An optional structured entity value.
+      // Must match entity type defined in schema if
+      // known. If this field is present, the `text` field could also be
+      // populated.
       oneof structured_value {
         // Money value. See also:
         // https://github.com/googleapis/googleapis/blob/master/google/type/money.proto
@@ -422,24 +462,29 @@ message Document {
         bool boolean_value = 6;
       }
 
-      // Required. Normalized entity value stored as a string. This field is populated for
-      // supported document type (e.g. Invoice). For some entity types, one of
-      // respective 'structured_value' fields may also be populated.
+      // Optional. An optional field to store a normalized string.
+      // For some entity types, one of respective `structured_value` fields may
+      // also be populated. Also not all the types of `structured_value` will be
+      // normalized. For example, some processors may not generate float
+      // or int normalized text by default.
       //
+      // Below are sample formats mapped to structured values.
       // - Money/Currency type (`money_value`) is in the ISO 4217 text format.
       // - Date type (`date_value`) is in the ISO 8601 text format.
       // - Datetime type (`datetime_value`) is in the ISO 8601 text format.
-      string text = 1 [(google.api.field_behavior) = REQUIRED];
+      string text = 1 [(google.api.field_behavior) = OPTIONAL];
     }
 
     // Optional. Provenance of the entity.
-    // Text anchor indexing into the [Document.text][google.cloud.documentai.v1beta3.Document.text].
+    // Text anchor indexing into the
+    // [Document.text][google.cloud.documentai.v1beta3.Document.text].
     TextAnchor text_anchor = 1 [(google.api.field_behavior) = OPTIONAL];
 
     // Entity type from a schema e.g. `Address`.
     string type = 2;
 
-    // Optional. Text value in the document e.g. `1600 Amphitheatre Pkwy`.
+    // Optional. Text value in the document e.g. `1600 Amphitheatre Pkwy`. If
+    // the entity is not present in the document, this field will be empty.
     string mention_text = 3 [(google.api.field_behavior) = OPTIONAL];
 
     // Optional. Deprecated.  Use `id` field instead.
@@ -448,32 +493,35 @@ message Document {
     // Optional. Confidence of detected Schema entity. Range [0, 1].
     float confidence = 5 [(google.api.field_behavior) = OPTIONAL];
 
-    // Optional. Represents the provenance of this entity wrt. the location on the
-    // page where it was found.
+    // Optional. Represents the provenance of this entity wrt. the location on
+    // the page where it was found.
     PageAnchor page_anchor = 6 [(google.api.field_behavior) = OPTIONAL];
 
     // Optional. Canonical id. This will be a unique value in the entity list
     // for this document.
     string id = 7 [(google.api.field_behavior) = OPTIONAL];
 
-    // Optional. Normalized entity value. Absent if the extracted value could not be
-    // converted or the type (e.g. address) is not supported for certain
+    // Optional. Normalized entity value. Absent if the extracted value could
+    // not be converted or the type (e.g. address) is not supported for certain
     // parsers. This field is also only populated for certain supported document
     // types.
-    NormalizedValue normalized_value = 9 [(google.api.field_behavior) = OPTIONAL];
+    NormalizedValue normalized_value = 9
+        [(google.api.field_behavior) = OPTIONAL];
 
-    // Optional. Entities can be nested to form a hierarchical data structure representing
-    // the content in the document.
+    // Optional. Entities can be nested to form a hierarchical data structure
+    // representing the content in the document.
     repeated Entity properties = 10 [(google.api.field_behavior) = OPTIONAL];
 
     // Optional. The history of this annotation.
     Provenance provenance = 11 [(google.api.field_behavior) = OPTIONAL];
 
-    // Optional. Whether the entity will be redacted for de-identification purposes.
+    // Optional. Whether the entity will be redacted for de-identification
+    // purposes.
     bool redacted = 12 [(google.api.field_behavior) = OPTIONAL];
   }
 
-  // Relationship between [Entities][google.cloud.documentai.v1beta3.Document.Entity].
+  // Relationship between
+  // [Entities][google.cloud.documentai.v1beta3.Document.Entity].
   message EntityRelation {
     // Subject entity id.
     string subject_id = 1;
@@ -485,30 +533,39 @@ message Document {
     string relation = 3;
   }
 
-  // Text reference indexing into the [Document.text][google.cloud.documentai.v1beta3.Document.text].
+  // Text reference indexing into the
+  // [Document.text][google.cloud.documentai.v1beta3.Document.text].
   message TextAnchor {
-    // A text segment in the [Document.text][google.cloud.documentai.v1beta3.Document.text]. The indices may be out of bounds
-    // which indicate that the text extends into another document shard for
-    // large sharded documents. See [ShardInfo.text_offset][google.cloud.documentai.v1beta3.Document.ShardInfo.text_offset]
+    // A text segment in the
+    // [Document.text][google.cloud.documentai.v1beta3.Document.text]. The
+    // indices may be out of bounds which indicate that the text extends into
+    // another document shard for large sharded documents. See
+    // [ShardInfo.text_offset][google.cloud.documentai.v1beta3.Document.ShardInfo.text_offset]
     message TextSegment {
-      // [TextSegment][google.cloud.documentai.v1beta3.Document.TextAnchor.TextSegment] start UTF-8 char index in the [Document.text][google.cloud.documentai.v1beta3.Document.text].
+      // [TextSegment][google.cloud.documentai.v1beta3.Document.TextAnchor.TextSegment]
+      // start UTF-8 char index in the
+      // [Document.text][google.cloud.documentai.v1beta3.Document.text].
       int64 start_index = 1;
 
-      // [TextSegment][google.cloud.documentai.v1beta3.Document.TextAnchor.TextSegment] half open end UTF-8 char index in the
+      // [TextSegment][google.cloud.documentai.v1beta3.Document.TextAnchor.TextSegment]
+      // half open end UTF-8 char index in the
       // [Document.text][google.cloud.documentai.v1beta3.Document.text].
       int64 end_index = 2;
     }
 
-    // The text segments from the [Document.text][google.cloud.documentai.v1beta3.Document.text].
+    // The text segments from the
+    // [Document.text][google.cloud.documentai.v1beta3.Document.text].
     repeated TextSegment text_segments = 1;
 
     // Contains the content of the text span so that users do
-    // not have to look it up in the text_segments.
+    // not have to look it up in the text_segments.  It is always
+    // populated for formFields.
     string content = 2;
   }
 
-  // Referencing the visual context of the entity in the [Document.pages][google.cloud.documentai.v1beta3.Document.pages].
-  // Page anchors can be cross-page, consist of multiple bounding polygons and
+  // Referencing the visual context of the entity in the
+  // [Document.pages][google.cloud.documentai.v1beta3.Document.pages]. Page
+  // anchors can be cross-page, consist of multiple bounding polygons and
   // optionally reference specific layout element types.
   message PageAnchor {
     // Represents a weak reference to a page element within a document.
@@ -518,47 +575,66 @@ message Document {
         // Layout Unspecified.
         LAYOUT_TYPE_UNSPECIFIED = 0;
 
-        // References a [Page.blocks][google.cloud.documentai.v1beta3.Document.Page.blocks] element.
+        // References a
+        // [Page.blocks][google.cloud.documentai.v1beta3.Document.Page.blocks]
+        // element.
         BLOCK = 1;
 
-        // References a [Page.paragraphs][google.cloud.documentai.v1beta3.Document.Page.paragraphs] element.
+        // References a
+        // [Page.paragraphs][google.cloud.documentai.v1beta3.Document.Page.paragraphs]
+        // element.
         PARAGRAPH = 2;
 
-        // References a [Page.lines][google.cloud.documentai.v1beta3.Document.Page.lines] element.
+        // References a
+        // [Page.lines][google.cloud.documentai.v1beta3.Document.Page.lines]
+        // element.
         LINE = 3;
 
-        // References a [Page.tokens][google.cloud.documentai.v1beta3.Document.Page.tokens] element.
+        // References a
+        // [Page.tokens][google.cloud.documentai.v1beta3.Document.Page.tokens]
+        // element.
         TOKEN = 4;
 
-        // References a [Page.visual_elements][google.cloud.documentai.v1beta3.Document.Page.visual_elements] element.
+        // References a
+        // [Page.visual_elements][google.cloud.documentai.v1beta3.Document.Page.visual_elements]
+        // element.
         VISUAL_ELEMENT = 5;
 
-        // Refrrences a [Page.tables][google.cloud.documentai.v1beta3.Document.Page.tables] element.
+        // Refrrences a
+        // [Page.tables][google.cloud.documentai.v1beta3.Document.Page.tables]
+        // element.
         TABLE = 6;
 
-        // References a [Page.form_fields][google.cloud.documentai.v1beta3.Document.Page.form_fields] element.
+        // References a
+        // [Page.form_fields][google.cloud.documentai.v1beta3.Document.Page.form_fields]
+        // element.
         FORM_FIELD = 7;
       }
 
-      // Required. Index into the [Document.pages][google.cloud.documentai.v1beta3.Document.pages] element, for example using
-      // [Document.pages][page_refs.page] to locate the related page element.
-      // This field is skipped when its value is the default 0. See
+      // Required. Index into the
+      // [Document.pages][google.cloud.documentai.v1beta3.Document.pages]
+      // element, for example using [Document.pages][page_refs.page] to locate
+      // the related page element. This field is skipped when its value is the
+      // default 0. See
       // https://developers.google.com/protocol-buffers/docs/proto3#json.
       int64 page = 1 [(google.api.field_behavior) = REQUIRED];
 
-      // Optional. The type of the layout element that is being referenced if any.
+      // Optional. The type of the layout element that is being referenced if
+      // any.
       LayoutType layout_type = 2 [(google.api.field_behavior) = OPTIONAL];
 
-      // Optional. Deprecated.  Use [PageRef.bounding_poly][google.cloud.documentai.v1beta3.Document.PageAnchor.PageRef.bounding_poly] instead.
-      string layout_id = 3 [
-        deprecated = true,
-        (google.api.field_behavior) = OPTIONAL
-      ];
+      // Optional. Deprecated.  Use
+      // [PageRef.bounding_poly][google.cloud.documentai.v1beta3.Document.PageAnchor.PageRef.bounding_poly]
+      // instead.
+      string layout_id = 3
+          [deprecated = true, (google.api.field_behavior) = OPTIONAL];
 
-      // Optional. Identifies the bounding polygon of a layout element on the page.
+      // Optional. Identifies the bounding polygon of a layout element on the
+      // page.
       BoundingPoly bounding_poly = 4 [(google.api.field_behavior) = OPTIONAL];
 
-      // Optional. Confidence of detected page element, if applicable. Range [0, 1].
+      // Optional. Confidence of detected page element, if applicable. Range [0,
+      // 1].
       float confidence = 5 [(google.api.field_behavior) = OPTIONAL];
     }
 
@@ -569,15 +645,14 @@ message Document {
   // Structure to identify provenance relationships between annotations in
   // different revisions.
   message Provenance {
-    // Structure for referencing parent provenances.  When an element replaces
-    // one of more other elements parent references identify the elements that
-    // are replaced.
+    // The parent element the current element is based on. Used for
+    // referencing/aligning, removal and replacement operations.
     message Parent {
-      // The index of the [Document.revisions] identifying the parent revision.
+      // The index of the index into current revision's parent_ids list.
       int32 revision = 1;
 
-      // The index of the parent revisions corresponding collection of items
-      // (eg. list of entities, properties within entities, etc.)
+      // The index of the parent item in the corresponding item list (eg. list
+      // of entities, properties within entities, etc.) in the parent revision.
       int32 index = 3;
 
       // The id of the parent provenance.
@@ -586,19 +661,20 @@ message Document {
 
     // If a processor or agent does an explicit operation on existing elements.
     enum OperationType {
-      // Operation type unspecified.
+      // Operation type unspecified. If no operation is specified a provenance
+      // entry is simply used to match against a `parent`.
       OPERATION_TYPE_UNSPECIFIED = 0;
 
-      // Add an element.  Implicit if no `parents` are set for the provenance.
+      // Add an element.
       ADD = 1;
 
-      // The element is removed.  No `parents` should be set.
+      // Remove an element identified by `parent`.
       REMOVE = 2;
 
-      // Explicitly replaces the element(s) identified by `parents`.
+      // Replace an element identified by `parent`.
       REPLACE = 3;
 
-      // Element is requested for human review.
+      // Request human review for the element identified by `parent`.
       EVAL_REQUESTED = 4;
 
       // Element is reviewed and approved at human review, confidence will be
@@ -664,10 +740,11 @@ message Document {
   // This message is used for text changes aka. OCR corrections.
   message TextChange {
     // Provenance of the correction.
-    // Text anchor indexing into the [Document.text][google.cloud.documentai.v1beta3.Document.text].  There can only be a
-    // single `TextAnchor.text_segments` element.  If the start and
-    // end index of the text segment are the same, the text change is inserted
-    // before that index.
+    // Text anchor indexing into the
+    // [Document.text][google.cloud.documentai.v1beta3.Document.text].  There
+    // can only be a single `TextAnchor.text_segments` element.  If the start
+    // and end index of the text segment are the same, the text change is
+    // inserted before that index.
     TextAnchor text_anchor = 1;
 
     // The text that replaces the text identified in the `text_anchor`.
@@ -700,22 +777,26 @@ message Document {
   // Optional. UTF-8 encoded text in reading order from the document.
   string text = 4 [(google.api.field_behavior) = OPTIONAL];
 
-  // Styles for the [Document.text][google.cloud.documentai.v1beta3.Document.text].
+  // Placeholder.  Styles for the
+  // [Document.text][google.cloud.documentai.v1beta3.Document.text].
   repeated Style text_styles = 5;
 
-  // Visual page layout for the [Document][google.cloud.documentai.v1beta3.Document].
+  // Visual page layout for the
+  // [Document][google.cloud.documentai.v1beta3.Document].
   repeated Page pages = 6;
 
-  // A list of entities detected on [Document.text][google.cloud.documentai.v1beta3.Document.text]. For document shards,
-  // entities in this list may cross shard boundaries.
+  // A list of entities detected on
+  // [Document.text][google.cloud.documentai.v1beta3.Document.text]. For
+  // document shards, entities in this list may cross shard boundaries.
   repeated Entity entities = 7;
 
-  // Relationship among [Document.entities][google.cloud.documentai.v1beta3.Document.entities].
+  // Placeholder.  Relationship among
+  // [Document.entities][google.cloud.documentai.v1beta3.Document.entities].
   repeated EntityRelation entity_relations = 8;
 
-  // A list of text corrections made to [Document.text].  This is usually
-  // used for annotating corrections to OCR mistakes.  Text changes for a given
-  // revision may not overlap with each other.
+  // Placeholder.  A list of text corrections made to [Document.text].  This is
+  // usually used for annotating corrections to OCR mistakes.  Text changes for
+  // a given revision may not overlap with each other.
   repeated TextChange text_changes = 14;
 
   // Information about the sharding if this document is sharded part of a larger
@@ -725,6 +806,6 @@ message Document {
   // Any error that occurred while processing this document.
   google.rpc.Status error = 10;
 
-  // Revision history of this document.
+  // Placeholder. Revision history of this document.
   repeated Revision revisions = 13;
 }
diff --git a/protos/protos.d.ts b/protos/protos.d.ts
index 6e5f5789d..acb31c79a 100644
--- a/protos/protos.d.ts
+++ b/protos/protos.d.ts
@@ -556,6 +556,9 @@ export namespace google {
                         /** Page formFields */
                         formFields?: (google.cloud.documentai.v1.Document.Page.IFormField[]|null);
 
+                        /** Page symbols */
+                        symbols?: (google.cloud.documentai.v1.Document.Page.ISymbol[]|null);
+
                         /** Page provenance */
                         provenance?: (google.cloud.documentai.v1.Document.IProvenance|null);
                     }
@@ -608,6 +611,9 @@ export namespace google {
                         /** Page formFields. */
                         public formFields: google.cloud.documentai.v1.Document.Page.IFormField[];
 
+                        /** Page symbols. */
+                        public symbols: google.cloud.documentai.v1.Document.Page.ISymbol[];
+
                         /** Page provenance. */
                         public provenance?: (google.cloud.documentai.v1.Document.IProvenance|null);
 
@@ -1640,6 +1646,102 @@ export namespace google {
                             }
                         }
 
+                        /** Properties of a Symbol. */
+                        interface ISymbol {
+
+                            /** Symbol layout */
+                            layout?: (google.cloud.documentai.v1.Document.Page.ILayout|null);
+
+                            /** Symbol detectedLanguages */
+                            detectedLanguages?: (google.cloud.documentai.v1.Document.Page.IDetectedLanguage[]|null);
+                        }
+
+                        /** Represents a Symbol. */
+                        class Symbol implements ISymbol {
+
+                            /**
+                             * Constructs a new Symbol.
+                             * @param [properties] Properties to set
+                             */
+                            constructor(properties?: google.cloud.documentai.v1.Document.Page.ISymbol);
+
+                            /** Symbol layout. */
+                            public layout?: (google.cloud.documentai.v1.Document.Page.ILayout|null);
+
+                            /** Symbol detectedLanguages. */
+                            public detectedLanguages: google.cloud.documentai.v1.Document.Page.IDetectedLanguage[];
+
+                            /**
+                             * Creates a new Symbol instance using the specified properties.
+                             * @param [properties] Properties to set
+                             * @returns Symbol instance
+                             */
+                            public static create(properties?: google.cloud.documentai.v1.Document.Page.ISymbol): google.cloud.documentai.v1.Document.Page.Symbol;
+
+                            /**
+                             * Encodes the specified Symbol message. Does not implicitly {@link google.cloud.documentai.v1.Document.Page.Symbol.verify|verify} messages.
+                             * @param message Symbol message or plain object to encode
+                             * @param [writer] Writer to encode to
+                             * @returns Writer
+                             */
+                            public static encode(message: google.cloud.documentai.v1.Document.Page.ISymbol, writer?: $protobuf.Writer): $protobuf.Writer;
+
+                            /**
+                             * Encodes the specified Symbol message, length delimited. Does not implicitly {@link google.cloud.documentai.v1.Document.Page.Symbol.verify|verify} messages.
+                             * @param message Symbol message or plain object to encode
+                             * @param [writer] Writer to encode to
+                             * @returns Writer
+                             */
+                            public static encodeDelimited(message: google.cloud.documentai.v1.Document.Page.ISymbol, writer?: $protobuf.Writer): $protobuf.Writer;
+
+                            /**
+                             * Decodes a Symbol message from the specified reader or buffer.
+                             * @param reader Reader or buffer to decode from
+                             * @param [length] Message length if known beforehand
+                             * @returns Symbol
+                             * @throws {Error} If the payload is not a reader or valid buffer
+                             * @throws {$protobuf.util.ProtocolError} If required fields are missing
+                             */
+                            public static decode(reader: ($protobuf.Reader|Uint8Array), length?: number): google.cloud.documentai.v1.Document.Page.Symbol;
+
+                            /**
+                             * Decodes a Symbol message from the specified reader or buffer, length delimited.
+                             * @param reader Reader or buffer to decode from
+                             * @returns Symbol
+                             * @throws {Error} If the payload is not a reader or valid buffer
+                             * @throws {$protobuf.util.ProtocolError} If required fields are missing
+                             */
+                            public static decodeDelimited(reader: ($protobuf.Reader|Uint8Array)): google.cloud.documentai.v1.Document.Page.Symbol;
+
+                            /**
+                             * Verifies a Symbol message.
+                             * @param message Plain object to verify
+                             * @returns `null` if valid, otherwise the reason why it is not
+                             */
+                            public static verify(message: { [k: string]: any }): (string|null);
+
+                            /**
+                             * Creates a Symbol message from a plain object. Also converts values to their respective internal types.
+                             * @param object Plain object
+                             * @returns Symbol
+                             */
+                            public static fromObject(object: { [k: string]: any }): google.cloud.documentai.v1.Document.Page.Symbol;
+
+                            /**
+                             * Creates a plain object from a Symbol message. Also converts values to other types if specified.
+                             * @param message Symbol
+                             * @param [options] Conversion options
+                             * @returns Plain object
+                             */
+                            public static toObject(message: google.cloud.documentai.v1.Document.Page.Symbol, options?: $protobuf.IConversionOptions): { [k: string]: any };
+
+                            /**
+                             * Converts this Symbol to JSON.
+                             * @returns JSON object
+                             */
+                            public toJSON(): { [k: string]: any };
+                        }
+
                         /** Properties of a VisualElement. */
                         interface IVisualElement {
 
@@ -15238,6 +15340,9 @@ export namespace google {
                         /** Page formFields */
                         formFields?: (google.cloud.documentai.v1beta3.Document.Page.IFormField[]|null);
 
+                        /** Page symbols */
+                        symbols?: (google.cloud.documentai.v1beta3.Document.Page.ISymbol[]|null);
+
                         /** Page provenance */
                         provenance?: (google.cloud.documentai.v1beta3.Document.IProvenance|null);
                     }
@@ -15290,6 +15395,9 @@ export namespace google {
                         /** Page formFields. */
                         public formFields: google.cloud.documentai.v1beta3.Document.Page.IFormField[];
 
+                        /** Page symbols. */
+                        public symbols: google.cloud.documentai.v1beta3.Document.Page.ISymbol[];
+
                         /** Page provenance. */
                         public provenance?: (google.cloud.documentai.v1beta3.Document.IProvenance|null);
 
@@ -16322,6 +16430,102 @@ export namespace google {
                             }
                         }
 
+                        /** Properties of a Symbol. */
+                        interface ISymbol {
+
+                            /** Symbol layout */
+                            layout?: (google.cloud.documentai.v1beta3.Document.Page.ILayout|null);
+
+                            /** Symbol detectedLanguages */
+                            detectedLanguages?: (google.cloud.documentai.v1beta3.Document.Page.IDetectedLanguage[]|null);
+                        }
+
+                        /** Represents a Symbol. */
+                        class Symbol implements ISymbol {
+
+                            /**
+                             * Constructs a new Symbol.
+                             * @param [properties] Properties to set
+                             */
+                            constructor(properties?: google.cloud.documentai.v1beta3.Document.Page.ISymbol);
+
+                            /** Symbol layout. */
+                            public layout?: (google.cloud.documentai.v1beta3.Document.Page.ILayout|null);
+
+                            /** Symbol detectedLanguages. */
+                            public detectedLanguages: google.cloud.documentai.v1beta3.Document.Page.IDetectedLanguage[];
+
+                            /**
+                             * Creates a new Symbol instance using the specified properties.
+                             * @param [properties] Properties to set
+                             * @returns Symbol instance
+                             */
+                            public static create(properties?: google.cloud.documentai.v1beta3.Document.Page.ISymbol): google.cloud.documentai.v1beta3.Document.Page.Symbol;
+
+                            /**
+                             * Encodes the specified Symbol message. Does not implicitly {@link google.cloud.documentai.v1beta3.Document.Page.Symbol.verify|verify} messages.
+                             * @param message Symbol message or plain object to encode
+                             * @param [writer] Writer to encode to
+                             * @returns Writer
+                             */
+                            public static encode(message: google.cloud.documentai.v1beta3.Document.Page.ISymbol, writer?: $protobuf.Writer): $protobuf.Writer;
+
+                            /**
+                             * Encodes the specified Symbol message, length delimited. Does not implicitly {@link google.cloud.documentai.v1beta3.Document.Page.Symbol.verify|verify} messages.
+                             * @param message Symbol message or plain object to encode
+                             * @param [writer] Writer to encode to
+                             * @returns Writer
+                             */
+                            public static encodeDelimited(message: google.cloud.documentai.v1beta3.Document.Page.ISymbol, writer?: $protobuf.Writer): $protobuf.Writer;
+
+                            /**
+                             * Decodes a Symbol message from the specified reader or buffer.
+                             * @param reader Reader or buffer to decode from
+                             * @param [length] Message length if known beforehand
+                             * @returns Symbol
+                             * @throws {Error} If the payload is not a reader or valid buffer
+                             * @throws {$protobuf.util.ProtocolError} If required fields are missing
+                             */
+                            public static decode(reader: ($protobuf.Reader|Uint8Array), length?: number): google.cloud.documentai.v1beta3.Document.Page.Symbol;
+
+                            /**
+                             * Decodes a Symbol message from the specified reader or buffer, length delimited.
+                             * @param reader Reader or buffer to decode from
+                             * @returns Symbol
+                             * @throws {Error} If the payload is not a reader or valid buffer
+                             * @throws {$protobuf.util.ProtocolError} If required fields are missing
+                             */
+                            public static decodeDelimited(reader: ($protobuf.Reader|Uint8Array)): google.cloud.documentai.v1beta3.Document.Page.Symbol;
+
+                            /**
+                             * Verifies a Symbol message.
+                             * @param message Plain object to verify
+                             * @returns `null` if valid, otherwise the reason why it is not
+                             */
+                            public static verify(message: { [k: string]: any }): (string|null);
+
+                            /**
+                             * Creates a Symbol message from a plain object. Also converts values to their respective internal types.
+                             * @param object Plain object
+                             * @returns Symbol
+                             */
+                            public static fromObject(object: { [k: string]: any }): google.cloud.documentai.v1beta3.Document.Page.Symbol;
+
+                            /**
+                             * Creates a plain object from a Symbol message. Also converts values to other types if specified.
+                             * @param message Symbol
+                             * @param [options] Conversion options
+                             * @returns Plain object
+                             */
+                            public static toObject(message: google.cloud.documentai.v1beta3.Document.Page.Symbol, options?: $protobuf.IConversionOptions): { [k: string]: any };
+
+                            /**
+                             * Converts this Symbol to JSON.
+                             * @returns JSON object
+                             */
+                            public toJSON(): { [k: string]: any };
+                        }
+
                         /** Properties of a VisualElement. */
                         interface IVisualElement {
 
@@ -22432,18 +22636,6 @@ export namespace google {
     /** Namespace api. */
     namespace api {
 
-        /** FieldBehavior enum. */
-        enum FieldBehavior {
-            FIELD_BEHAVIOR_UNSPECIFIED = 0,
-            OPTIONAL = 1,
-            REQUIRED = 2,
-            OUTPUT_ONLY = 3,
-            INPUT_ONLY = 4,
-            IMMUTABLE = 5,
-            UNORDERED_LIST = 6,
-            NON_EMPTY_DEFAULT = 7
-        }
-
         /** Properties of a Http. */
         interface IHttp {
 
@@ -22783,6 +22975,18 @@ export namespace google {
             public toJSON(): { [k: string]: any };
         }
 
+        /** FieldBehavior enum. */
+        enum FieldBehavior {
+            FIELD_BEHAVIOR_UNSPECIFIED = 0,
+            OPTIONAL = 1,
+            REQUIRED = 2,
+            OUTPUT_ONLY = 3,
+            INPUT_ONLY = 4,
+            IMMUTABLE = 5,
+            UNORDERED_LIST = 6,
+            NON_EMPTY_DEFAULT = 7
+        }
+
         /** Properties of a ResourceDescriptor. */
         interface IResourceDescriptor {
 
diff --git a/protos/protos.js b/protos/protos.js
index e2761b092..cfa1f8eac 100644
--- a/protos/protos.js
+++ b/protos/protos.js
@@ -1502,6 +1502,7 @@
                              * @property {Array.<google.cloud.documentai.v1.Document.Page.IVisualElement>|null} [visualElements] Page visualElements
                              * @property {Array.<google.cloud.documentai.v1.Document.Page.ITable>|null} [tables] Page tables
                              * @property {Array.<google.cloud.documentai.v1.Document.Page.IFormField>|null} [formFields] Page formFields
+                             * @property {Array.<google.cloud.documentai.v1.Document.Page.ISymbol>|null} [symbols] Page symbols
                              * @property {google.cloud.documentai.v1.Document.IProvenance|null} [provenance] Page provenance
                              */
     
@@ -1523,6 +1524,7 @@
                                 this.visualElements = [];
                                 this.tables = [];
                                 this.formFields = [];
+                                this.symbols = [];
                                 if (properties)
                                     for (var keys = Object.keys(properties), i = 0; i < keys.length; ++i)
                                         if (properties[keys[i]] != null)
@@ -1633,6 +1635,14 @@
                              */
                             Page.prototype.formFields = $util.emptyArray;
     
+                            /**
+                             * Page symbols.
+                             * @member {Array.<google.cloud.documentai.v1.Document.Page.ISymbol>} symbols
+                             * @memberof google.cloud.documentai.v1.Document.Page
+                             * @instance
+                             */
+                            Page.prototype.symbols = $util.emptyArray;
+    
                             /**
                              * Page provenance.
                              * @member {google.cloud.documentai.v1.Document.IProvenance|null|undefined} provenance
@@ -1695,6 +1705,9 @@
                                 if (message.formFields != null && message.formFields.length)
                                     for (var i = 0; i < message.formFields.length; ++i)
                                         $root.google.cloud.documentai.v1.Document.Page.FormField.encode(message.formFields[i], writer.uint32(/* id 11, wireType 2 =*/90).fork()).ldelim();
+                                if (message.symbols != null && message.symbols.length)
+                                    for (var i = 0; i < message.symbols.length; ++i)
+                                        $root.google.cloud.documentai.v1.Document.Page.Symbol.encode(message.symbols[i], writer.uint32(/* id 12, wireType 2 =*/98).fork()).ldelim();
                                 if (message.image != null && Object.hasOwnProperty.call(message, "image"))
                                     $root.google.cloud.documentai.v1.Document.Page.Image.encode(message.image, writer.uint32(/* id 13, wireType 2 =*/106).fork()).ldelim();
                                 if (message.transforms != null && message.transforms.length)
@@ -1793,6 +1806,11 @@
                                             message.formFields = [];
                                         message.formFields.push($root.google.cloud.documentai.v1.Document.Page.FormField.decode(reader, reader.uint32()));
                                         break;
+                                    case 12:
+                                        if (!(message.symbols && message.symbols.length))
+                                            message.symbols = [];
+                                        message.symbols.push($root.google.cloud.documentai.v1.Document.Page.Symbol.decode(reader, reader.uint32()));
+                                        break;
                                     case 16:
                                         message.provenance = $root.google.cloud.documentai.v1.Document.Provenance.decode(reader, reader.uint32());
                                         break;
@@ -1930,6 +1948,15 @@
                                             return "formFields." + error;
                                     }
                                 }
+                                if (message.symbols != null && message.hasOwnProperty("symbols")) {
+                                    if (!Array.isArray(message.symbols))
+                                        return "symbols: array expected";
+                                    for (var i = 0; i < message.symbols.length; ++i) {
+                                        var error = $root.google.cloud.documentai.v1.Document.Page.Symbol.verify(message.symbols[i]);
+                                        if (error)
+                                            return "symbols." + error;
+                                    }
+                                }
                                 if (message.provenance != null && message.hasOwnProperty("provenance")) {
                                     var error = $root.google.cloud.documentai.v1.Document.Provenance.verify(message.provenance);
                                     if (error)
@@ -2057,6 +2084,16 @@
                                         message.formFields[i] = $root.google.cloud.documentai.v1.Document.Page.FormField.fromObject(object.formFields[i]);
                                     }
                                 }
+                                if (object.symbols) {
+                                    if (!Array.isArray(object.symbols))
+                                        throw TypeError(".google.cloud.documentai.v1.Document.Page.symbols: array expected");
+                                    message.symbols = [];
+                                    for (var i = 0; i < object.symbols.length; ++i) {
+                                        if (typeof object.symbols[i] !== "object")
+                                            throw TypeError(".google.cloud.documentai.v1.Document.Page.symbols: object expected");
+                                        message.symbols[i] = $root.google.cloud.documentai.v1.Document.Page.Symbol.fromObject(object.symbols[i]);
+                                    }
+                                }
                                 if (object.provenance != null) {
                                     if (typeof object.provenance !== "object")
                                         throw TypeError(".google.cloud.documentai.v1.Document.Page.provenance: object expected");
@@ -2087,6 +2124,7 @@
                                     object.visualElements = [];
                                     object.tables = [];
                                     object.formFields = [];
+                                    object.symbols = [];
                                     object.transforms = [];
                                 }
                                 if (options.defaults) {
@@ -2142,6 +2180,11 @@
                                     for (var j = 0; j < message.formFields.length; ++j)
                                         object.formFields[j] = $root.google.cloud.documentai.v1.Document.Page.FormField.toObject(message.formFields[j], options);
                                 }
+                                if (message.symbols && message.symbols.length) {
+                                    object.symbols = [];
+                                    for (var j = 0; j < message.symbols.length; ++j)
+                                        object.symbols[j] = $root.google.cloud.documentai.v1.Document.Page.Symbol.toObject(message.symbols[j], options);
+                                }
                                 if (message.image != null && message.hasOwnProperty("image"))
                                     object.image = $root.google.cloud.documentai.v1.Document.Page.Image.toObject(message.image, options);
                                 if (message.transforms && message.transforms.length) {
@@ -4546,6 +4589,242 @@
                                 return Token;
                             })();
     
+                            Page.Symbol = (function() {
+    
+                                /**
+                                 * Properties of a Symbol.
+                                 * @memberof google.cloud.documentai.v1.Document.Page
+                                 * @interface ISymbol
+                                 * @property {google.cloud.documentai.v1.Document.Page.ILayout|null} [layout] Symbol layout
+                                 * @property {Array.<google.cloud.documentai.v1.Document.Page.IDetectedLanguage>|null} [detectedLanguages] Symbol detectedLanguages
+                                 */
+    
+                                /**
+                                 * Constructs a new Symbol.
+                                 * @memberof google.cloud.documentai.v1.Document.Page
+                                 * @classdesc Represents a Symbol.
+                                 * @implements ISymbol
+                                 * @constructor
+                                 * @param {google.cloud.documentai.v1.Document.Page.ISymbol=} [properties] Properties to set
+                                 */
+                                function Symbol(properties) {
+                                    this.detectedLanguages = [];
+                                    if (properties)
+                                        for (var keys = Object.keys(properties), i = 0; i < keys.length; ++i)
+                                            if (properties[keys[i]] != null)
+                                                this[keys[i]] = properties[keys[i]];
+                                }
+    
+                                /**
+                                 * Symbol layout.
+                                 * @member {google.cloud.documentai.v1.Document.Page.ILayout|null|undefined} layout
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @instance
+                                 */
+                                Symbol.prototype.layout = null;
+    
+                                /**
+                                 * Symbol detectedLanguages.
+                                 * @member {Array.<google.cloud.documentai.v1.Document.Page.IDetectedLanguage>} detectedLanguages
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @instance
+                                 */
+                                Symbol.prototype.detectedLanguages = $util.emptyArray;
+    
+                                /**
+                                 * Creates a new Symbol instance using the specified properties.
+                                 * @function create
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @static
+                                 * @param {google.cloud.documentai.v1.Document.Page.ISymbol=} [properties] Properties to set
+                                 * @returns {google.cloud.documentai.v1.Document.Page.Symbol} Symbol instance
+                                 */
+                                Symbol.create = function create(properties) {
+                                    return new Symbol(properties);
+                                };
+    
+                                /**
+                                 * Encodes the specified Symbol message. Does not implicitly {@link google.cloud.documentai.v1.Document.Page.Symbol.verify|verify} messages.
+                                 * @function encode
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @static
+                                 * @param {google.cloud.documentai.v1.Document.Page.ISymbol} message Symbol message or plain object to encode
+                                 * @param {$protobuf.Writer} [writer] Writer to encode to
+                                 * @returns {$protobuf.Writer} Writer
+                                 */
+                                Symbol.encode = function encode(message, writer) {
+                                    if (!writer)
+                                        writer = $Writer.create();
+                                    if (message.layout != null && Object.hasOwnProperty.call(message, "layout"))
+                                        $root.google.cloud.documentai.v1.Document.Page.Layout.encode(message.layout, writer.uint32(/* id 1, wireType 2 =*/10).fork()).ldelim();
+                                    if (message.detectedLanguages != null && message.detectedLanguages.length)
+                                        for (var i = 0; i < message.detectedLanguages.length; ++i)
+                                            $root.google.cloud.documentai.v1.Document.Page.DetectedLanguage.encode(message.detectedLanguages[i], writer.uint32(/* id 2, wireType 2 =*/18).fork()).ldelim();
+                                    return writer;
+                                };
+    
+                                /**
+                                 * Encodes the specified Symbol message, length delimited. Does not implicitly {@link google.cloud.documentai.v1.Document.Page.Symbol.verify|verify} messages.
+                                 * @function encodeDelimited
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @static
+                                 * @param {google.cloud.documentai.v1.Document.Page.ISymbol} message Symbol message or plain object to encode
+                                 * @param {$protobuf.Writer} [writer] Writer to encode to
+                                 * @returns {$protobuf.Writer} Writer
+                                 */
+                                Symbol.encodeDelimited = function encodeDelimited(message, writer) {
+                                    return this.encode(message, writer).ldelim();
+                                };
+    
+                                /**
+                                 * Decodes a Symbol message from the specified reader or buffer.
+                                 * @function decode
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @static
+                                 * @param {$protobuf.Reader|Uint8Array} reader Reader or buffer to decode from
+                                 * @param {number} [length] Message length if known beforehand
+                                 * @returns {google.cloud.documentai.v1.Document.Page.Symbol} Symbol
+                                 * @throws {Error} If the payload is not a reader or valid buffer
+                                 * @throws {$protobuf.util.ProtocolError} If required fields are missing
+                                 */
+                                Symbol.decode = function decode(reader, length) {
+                                    if (!(reader instanceof $Reader))
+                                        reader = $Reader.create(reader);
+                                    var end = length === undefined ? reader.len : reader.pos + length, message = new $root.google.cloud.documentai.v1.Document.Page.Symbol();
+                                    while (reader.pos < end) {
+                                        var tag = reader.uint32();
+                                        switch (tag >>> 3) {
+                                        case 1:
+                                            message.layout = $root.google.cloud.documentai.v1.Document.Page.Layout.decode(reader, reader.uint32());
+                                            break;
+                                        case 2:
+                                            if (!(message.detectedLanguages && message.detectedLanguages.length))
+                                                message.detectedLanguages = [];
+                                            message.detectedLanguages.push($root.google.cloud.documentai.v1.Document.Page.DetectedLanguage.decode(reader, reader.uint32()));
+                                            break;
+                                        default:
+                                            reader.skipType(tag & 7);
+                                            break;
+                                        }
+                                    }
+                                    return message;
+                                };
+    
+                                /**
+                                 * Decodes a Symbol message from the specified reader or buffer, length delimited.
+                                 * @function decodeDelimited
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @static
+                                 * @param {$protobuf.Reader|Uint8Array} reader Reader or buffer to decode from
+                                 * @returns {google.cloud.documentai.v1.Document.Page.Symbol} Symbol
+                                 * @throws {Error} If the payload is not a reader or valid buffer
+                                 * @throws {$protobuf.util.ProtocolError} If required fields are missing
+                                 */
+                                Symbol.decodeDelimited = function decodeDelimited(reader) {
+                                    if (!(reader instanceof $Reader))
+                                        reader = new $Reader(reader);
+                                    return this.decode(reader, reader.uint32());
+                                };
+    
+                                /**
+                                 * Verifies a Symbol message.
+                                 * @function verify
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @static
+                                 * @param {Object.<string,*>} message Plain object to verify
+                                 * @returns {string|null} `null` if valid, otherwise the reason why it is not
+                                 */
+                                Symbol.verify = function verify(message) {
+                                    if (typeof message !== "object" || message === null)
+                                        return "object expected";
+                                    if (message.layout != null && message.hasOwnProperty("layout")) {
+                                        var error = $root.google.cloud.documentai.v1.Document.Page.Layout.verify(message.layout);
+                                        if (error)
+                                            return "layout." + error;
+                                    }
+                                    if (message.detectedLanguages != null && message.hasOwnProperty("detectedLanguages")) {
+                                        if (!Array.isArray(message.detectedLanguages))
+                                            return "detectedLanguages: array expected";
+                                        for (var i = 0; i < message.detectedLanguages.length; ++i) {
+                                            var error = $root.google.cloud.documentai.v1.Document.Page.DetectedLanguage.verify(message.detectedLanguages[i]);
+                                            if (error)
+                                                return "detectedLanguages." + error;
+                                        }
+                                    }
+                                    return null;
+                                };
+    
+                                /**
+                                 * Creates a Symbol message from a plain object. Also converts values to their respective internal types.
+                                 * @function fromObject
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @static
+                                 * @param {Object.<string,*>} object Plain object
+                                 * @returns {google.cloud.documentai.v1.Document.Page.Symbol} Symbol
+                                 */
+                                Symbol.fromObject = function fromObject(object) {
+                                    if (object instanceof $root.google.cloud.documentai.v1.Document.Page.Symbol)
+                                        return object;
+                                    var message = new $root.google.cloud.documentai.v1.Document.Page.Symbol();
+                                    if (object.layout != null) {
+                                        if (typeof object.layout !== "object")
+                                            throw TypeError(".google.cloud.documentai.v1.Document.Page.Symbol.layout: object expected");
+                                        message.layout = $root.google.cloud.documentai.v1.Document.Page.Layout.fromObject(object.layout);
+                                    }
+                                    if (object.detectedLanguages) {
+                                        if (!Array.isArray(object.detectedLanguages))
+                                            throw TypeError(".google.cloud.documentai.v1.Document.Page.Symbol.detectedLanguages: array expected");
+                                        message.detectedLanguages = [];
+                                        for (var i = 0; i < object.detectedLanguages.length; ++i) {
+                                            if (typeof object.detectedLanguages[i] !== "object")
+                                                throw TypeError(".google.cloud.documentai.v1.Document.Page.Symbol.detectedLanguages: object expected");
+                                            message.detectedLanguages[i] = $root.google.cloud.documentai.v1.Document.Page.DetectedLanguage.fromObject(object.detectedLanguages[i]);
+                                        }
+                                    }
+                                    return message;
+                                };
+    
+                                /**
+                                 * Creates a plain object from a Symbol message. Also converts values to other types if specified.
+                                 * @function toObject
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @static
+                                 * @param {google.cloud.documentai.v1.Document.Page.Symbol} message Symbol
+                                 * @param {$protobuf.IConversionOptions} [options] Conversion options
+                                 * @returns {Object.<string,*>} Plain object
+                                 */
+                                Symbol.toObject = function toObject(message, options) {
+                                    if (!options)
+                                        options = {};
+                                    var object = {};
+                                    if (options.arrays || options.defaults)
+                                        object.detectedLanguages = [];
+                                    if (options.defaults)
+                                        object.layout = null;
+                                    if (message.layout != null && message.hasOwnProperty("layout"))
+                                        object.layout = $root.google.cloud.documentai.v1.Document.Page.Layout.toObject(message.layout, options);
+                                    if (message.detectedLanguages && message.detectedLanguages.length) {
+                                        object.detectedLanguages = [];
+                                        for (var j = 0; j < message.detectedLanguages.length; ++j)
+                                            object.detectedLanguages[j] = $root.google.cloud.documentai.v1.Document.Page.DetectedLanguage.toObject(message.detectedLanguages[j], options);
+                                    }
+                                    return object;
+                                };
+    
+                                /**
+                                 * Converts this Symbol to JSON.
+                                 * @function toJSON
+                                 * @memberof google.cloud.documentai.v1.Document.Page.Symbol
+                                 * @instance
+                                 * @returns {Object.<string,*>} JSON object
+                                 */
+                                Symbol.prototype.toJSON = function toJSON() {
+                                    return this.constructor.toObject(this, $protobuf.util.toJSONOptions);
+                                };
+    
+                                return Symbol;
+                            })();
+    
                             Page.VisualElement = (function() {
     
                                 /**
@@ -38618,6 +38897,7 @@
                              * @property {Array.<google.cloud.documentai.v1beta3.Document.Page.IVisualElement>|null} [visualElements] Page visualElements
                              * @property {Array.<google.cloud.documentai.v1beta3.Document.Page.ITable>|null} [tables] Page tables
                              * @property {Array.<google.cloud.documentai.v1beta3.Document.Page.IFormField>|null} [formFields] Page formFields
+                             * @property {Array.<google.cloud.documentai.v1beta3.Document.Page.ISymbol>|null} [symbols] Page symbols
                              * @property {google.cloud.documentai.v1beta3.Document.IProvenance|null} [provenance] Page provenance
                              */
     
@@ -38639,6 +38919,7 @@
                                 this.visualElements = [];
                                 this.tables = [];
                                 this.formFields = [];
+                                this.symbols = [];
                                 if (properties)
                                     for (var keys = Object.keys(properties), i = 0; i < keys.length; ++i)
                                         if (properties[keys[i]] != null)
@@ -38749,6 +39030,14 @@
                              */
                             Page.prototype.formFields = $util.emptyArray;
     
+                            /**
+                             * Page symbols.
+                             * @member {Array.<google.cloud.documentai.v1beta3.Document.Page.ISymbol>} symbols
+                             * @memberof google.cloud.documentai.v1beta3.Document.Page
+                             * @instance
+                             */
+                            Page.prototype.symbols = $util.emptyArray;
+    
                             /**
                              * Page provenance.
                              * @member {google.cloud.documentai.v1beta3.Document.IProvenance|null|undefined} provenance
@@ -38811,6 +39100,9 @@
                                 if (message.formFields != null && message.formFields.length)
                                     for (var i = 0; i < message.formFields.length; ++i)
                                         $root.google.cloud.documentai.v1beta3.Document.Page.FormField.encode(message.formFields[i], writer.uint32(/* id 11, wireType 2 =*/90).fork()).ldelim();
+                                if (message.symbols != null && message.symbols.length)
+                                    for (var i = 0; i < message.symbols.length; ++i)
+                                        $root.google.cloud.documentai.v1beta3.Document.Page.Symbol.encode(message.symbols[i], writer.uint32(/* id 12, wireType 2 =*/98).fork()).ldelim();
                                 if (message.image != null && Object.hasOwnProperty.call(message, "image"))
                                     $root.google.cloud.documentai.v1beta3.Document.Page.Image.encode(message.image, writer.uint32(/* id 13, wireType 2 =*/106).fork()).ldelim();
                                 if (message.transforms != null && message.transforms.length)
@@ -38909,6 +39201,11 @@
                                             message.formFields = [];
                                         message.formFields.push($root.google.cloud.documentai.v1beta3.Document.Page.FormField.decode(reader, reader.uint32()));
                                         break;
+                                    case 12:
+                                        if (!(message.symbols && message.symbols.length))
+                                            message.symbols = [];
+                                        message.symbols.push($root.google.cloud.documentai.v1beta3.Document.Page.Symbol.decode(reader, reader.uint32()));
+                                        break;
                                     case 16:
                                         message.provenance = $root.google.cloud.documentai.v1beta3.Document.Provenance.decode(reader, reader.uint32());
                                         break;
@@ -39046,6 +39343,15 @@
                                             return "formFields." + error;
                                     }
                                 }
+                                if (message.symbols != null && message.hasOwnProperty("symbols")) {
+                                    if (!Array.isArray(message.symbols))
+                                        return "symbols: array expected";
+                                    for (var i = 0; i < message.symbols.length; ++i) {
+                                        var error = $root.google.cloud.documentai.v1beta3.Document.Page.Symbol.verify(message.symbols[i]);
+                                        if (error)
+                                            return "symbols." + error;
+                                    }
+                                }
                                 if (message.provenance != null && message.hasOwnProperty("provenance")) {
                                     var error = $root.google.cloud.documentai.v1beta3.Document.Provenance.verify(message.provenance);
                                     if (error)
@@ -39173,6 +39479,16 @@
                                         message.formFields[i] = $root.google.cloud.documentai.v1beta3.Document.Page.FormField.fromObject(object.formFields[i]);
                                     }
                                 }
+                                if (object.symbols) {
+                                    if (!Array.isArray(object.symbols))
+                                        throw TypeError(".google.cloud.documentai.v1beta3.Document.Page.symbols: array expected");
+                                    message.symbols = [];
+                                    for (var i = 0; i < object.symbols.length; ++i) {
+                                        if (typeof object.symbols[i] !== "object")
+                                            throw TypeError(".google.cloud.documentai.v1beta3.Document.Page.symbols: object expected");
+                                        message.symbols[i] = $root.google.cloud.documentai.v1beta3.Document.Page.Symbol.fromObject(object.symbols[i]);
+                                    }
+                                }
                                 if (object.provenance != null) {
                                     if (typeof object.provenance !== "object")
                                         throw TypeError(".google.cloud.documentai.v1beta3.Document.Page.provenance: object expected");
@@ -39203,6 +39519,7 @@
                                     object.visualElements = [];
                                     object.tables = [];
                                     object.formFields = [];
+                                    object.symbols = [];
                                     object.transforms = [];
                                 }
                                 if (options.defaults) {
@@ -39258,6 +39575,11 @@
                                     for (var j = 0; j < message.formFields.length; ++j)
                                         object.formFields[j] = $root.google.cloud.documentai.v1beta3.Document.Page.FormField.toObject(message.formFields[j], options);
                                 }
+                                if (message.symbols && message.symbols.length) {
+                                    object.symbols = [];
+                                    for (var j = 0; j < message.symbols.length; ++j)
+                                        object.symbols[j] = $root.google.cloud.documentai.v1beta3.Document.Page.Symbol.toObject(message.symbols[j], options);
+                                }
                                 if (message.image != null && message.hasOwnProperty("image"))
                                     object.image = $root.google.cloud.documentai.v1beta3.Document.Page.Image.toObject(message.image, options);
                                 if (message.transforms && message.transforms.length) {
@@ -41662,6 +41984,242 @@
                                 return Token;
                             })();
     
+                            Page.Symbol = (function() {
+    
+                                /**
+                                 * Properties of a Symbol.
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page
+                                 * @interface ISymbol
+                                 * @property {google.cloud.documentai.v1beta3.Document.Page.ILayout|null} [layout] Symbol layout
+                                 * @property {Array.<google.cloud.documentai.v1beta3.Document.Page.IDetectedLanguage>|null} [detectedLanguages] Symbol detectedLanguages
+                                 */
+    
+                                /**
+                                 * Constructs a new Symbol.
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page
+                                 * @classdesc Represents a Symbol.
+                                 * @implements ISymbol
+                                 * @constructor
+                                 * @param {google.cloud.documentai.v1beta3.Document.Page.ISymbol=} [properties] Properties to set
+                                 */
+                                function Symbol(properties) {
+                                    this.detectedLanguages = [];
+                                    if (properties)
+                                        for (var keys = Object.keys(properties), i = 0; i < keys.length; ++i)
+                                            if (properties[keys[i]] != null)
+                                                this[keys[i]] = properties[keys[i]];
+                                }
+    
+                                /**
+                                 * Symbol layout.
+                                 * @member {google.cloud.documentai.v1beta3.Document.Page.ILayout|null|undefined} layout
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @instance
+                                 */
+                                Symbol.prototype.layout = null;
+    
+                                /**
+                                 * Symbol detectedLanguages.
+                                 * @member {Array.<google.cloud.documentai.v1beta3.Document.Page.IDetectedLanguage>} detectedLanguages
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @instance
+                                 */
+                                Symbol.prototype.detectedLanguages = $util.emptyArray;
+    
+                                /**
+                                 * Creates a new Symbol instance using the specified properties.
+                                 * @function create
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @static
+                                 * @param {google.cloud.documentai.v1beta3.Document.Page.ISymbol=} [properties] Properties to set
+                                 * @returns {google.cloud.documentai.v1beta3.Document.Page.Symbol} Symbol instance
+                                 */
+                                Symbol.create = function create(properties) {
+                                    return new Symbol(properties);
+                                };
+    
+                                /**
+                                 * Encodes the specified Symbol message. Does not implicitly {@link google.cloud.documentai.v1beta3.Document.Page.Symbol.verify|verify} messages.
+                                 * @function encode
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @static
+                                 * @param {google.cloud.documentai.v1beta3.Document.Page.ISymbol} message Symbol message or plain object to encode
+                                 * @param {$protobuf.Writer} [writer] Writer to encode to
+                                 * @returns {$protobuf.Writer} Writer
+                                 */
+                                Symbol.encode = function encode(message, writer) {
+                                    if (!writer)
+                                        writer = $Writer.create();
+                                    if (message.layout != null && Object.hasOwnProperty.call(message, "layout"))
+                                        $root.google.cloud.documentai.v1beta3.Document.Page.Layout.encode(message.layout, writer.uint32(/* id 1, wireType 2 =*/10).fork()).ldelim();
+                                    if (message.detectedLanguages != null && message.detectedLanguages.length)
+                                        for (var i = 0; i < message.detectedLanguages.length; ++i)
+                                            $root.google.cloud.documentai.v1beta3.Document.Page.DetectedLanguage.encode(message.detectedLanguages[i], writer.uint32(/* id 2, wireType 2 =*/18).fork()).ldelim();
+                                    return writer;
+                                };
+    
+                                /**
+                                 * Encodes the specified Symbol message, length delimited. Does not implicitly {@link google.cloud.documentai.v1beta3.Document.Page.Symbol.verify|verify} messages.
+                                 * @function encodeDelimited
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @static
+                                 * @param {google.cloud.documentai.v1beta3.Document.Page.ISymbol} message Symbol message or plain object to encode
+                                 * @param {$protobuf.Writer} [writer] Writer to encode to
+                                 * @returns {$protobuf.Writer} Writer
+                                 */
+                                Symbol.encodeDelimited = function encodeDelimited(message, writer) {
+                                    return this.encode(message, writer).ldelim();
+                                };
+    
+                                /**
+                                 * Decodes a Symbol message from the specified reader or buffer.
+                                 * @function decode
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @static
+                                 * @param {$protobuf.Reader|Uint8Array} reader Reader or buffer to decode from
+                                 * @param {number} [length] Message length if known beforehand
+                                 * @returns {google.cloud.documentai.v1beta3.Document.Page.Symbol} Symbol
+                                 * @throws {Error} If the payload is not a reader or valid buffer
+                                 * @throws {$protobuf.util.ProtocolError} If required fields are missing
+                                 */
+                                Symbol.decode = function decode(reader, length) {
+                                    if (!(reader instanceof $Reader))
+                                        reader = $Reader.create(reader);
+                                    var end = length === undefined ? reader.len : reader.pos + length, message = new $root.google.cloud.documentai.v1beta3.Document.Page.Symbol();
+                                    while (reader.pos < end) {
+                                        var tag = reader.uint32();
+                                        switch (tag >>> 3) {
+                                        case 1:
+                                            message.layout = $root.google.cloud.documentai.v1beta3.Document.Page.Layout.decode(reader, reader.uint32());
+                                            break;
+                                        case 2:
+                                            if (!(message.detectedLanguages && message.detectedLanguages.length))
+                                                message.detectedLanguages = [];
+                                            message.detectedLanguages.push($root.google.cloud.documentai.v1beta3.Document.Page.DetectedLanguage.decode(reader, reader.uint32()));
+                                            break;
+                                        default:
+                                            reader.skipType(tag & 7);
+                                            break;
+                                        }
+                                    }
+                                    return message;
+                                };
+    
+                                /**
+                                 * Decodes a Symbol message from the specified reader or buffer, length delimited.
+                                 * @function decodeDelimited
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @static
+                                 * @param {$protobuf.Reader|Uint8Array} reader Reader or buffer to decode from
+                                 * @returns {google.cloud.documentai.v1beta3.Document.Page.Symbol} Symbol
+                                 * @throws {Error} If the payload is not a reader or valid buffer
+                                 * @throws {$protobuf.util.ProtocolError} If required fields are missing
+                                 */
+                                Symbol.decodeDelimited = function decodeDelimited(reader) {
+                                    if (!(reader instanceof $Reader))
+                                        reader = new $Reader(reader);
+                                    return this.decode(reader, reader.uint32());
+                                };
+    
+                                /**
+                                 * Verifies a Symbol message.
+                                 * @function verify
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @static
+                                 * @param {Object.<string,*>} message Plain object to verify
+                                 * @returns {string|null} `null` if valid, otherwise the reason why it is not
+                                 */
+                                Symbol.verify = function verify(message) {
+                                    if (typeof message !== "object" || message === null)
+                                        return "object expected";
+                                    if (message.layout != null && message.hasOwnProperty("layout")) {
+                                        var error = $root.google.cloud.documentai.v1beta3.Document.Page.Layout.verify(message.layout);
+                                        if (error)
+                                            return "layout." + error;
+                                    }
+                                    if (message.detectedLanguages != null && message.hasOwnProperty("detectedLanguages")) {
+                                        if (!Array.isArray(message.detectedLanguages))
+                                            return "detectedLanguages: array expected";
+                                        for (var i = 0; i < message.detectedLanguages.length; ++i) {
+                                            var error = $root.google.cloud.documentai.v1beta3.Document.Page.DetectedLanguage.verify(message.detectedLanguages[i]);
+                                            if (error)
+                                                return "detectedLanguages." + error;
+                                        }
+                                    }
+                                    return null;
+                                };
+    
+                                /**
+                                 * Creates a Symbol message from a plain object. Also converts values to their respective internal types.
+                                 * @function fromObject
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @static
+                                 * @param {Object.<string,*>} object Plain object
+                                 * @returns {google.cloud.documentai.v1beta3.Document.Page.Symbol} Symbol
+                                 */
+                                Symbol.fromObject = function fromObject(object) {
+                                    if (object instanceof $root.google.cloud.documentai.v1beta3.Document.Page.Symbol)
+                                        return object;
+                                    var message = new $root.google.cloud.documentai.v1beta3.Document.Page.Symbol();
+                                    if (object.layout != null) {
+                                        if (typeof object.layout !== "object")
+                                            throw TypeError(".google.cloud.documentai.v1beta3.Document.Page.Symbol.layout: object expected");
+                                        message.layout = $root.google.cloud.documentai.v1beta3.Document.Page.Layout.fromObject(object.layout);
+                                    }
+                                    if (object.detectedLanguages) {
+                                        if (!Array.isArray(object.detectedLanguages))
+                                            throw TypeError(".google.cloud.documentai.v1beta3.Document.Page.Symbol.detectedLanguages: array expected");
+                                        message.detectedLanguages = [];
+                                        for (var i = 0; i < object.detectedLanguages.length; ++i) {
+                                            if (typeof object.detectedLanguages[i] !== "object")
+                                                throw TypeError(".google.cloud.documentai.v1beta3.Document.Page.Symbol.detectedLanguages: object expected");
+                                            message.detectedLanguages[i] = $root.google.cloud.documentai.v1beta3.Document.Page.DetectedLanguage.fromObject(object.detectedLanguages[i]);
+                                        }
+                                    }
+                                    return message;
+                                };
+    
+                                /**
+                                 * Creates a plain object from a Symbol message. Also converts values to other types if specified.
+                                 * @function toObject
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @static
+                                 * @param {google.cloud.documentai.v1beta3.Document.Page.Symbol} message Symbol
+                                 * @param {$protobuf.IConversionOptions} [options] Conversion options
+                                 * @returns {Object.<string,*>} Plain object
+                                 */
+                                Symbol.toObject = function toObject(message, options) {
+                                    if (!options)
+                                        options = {};
+                                    var object = {};
+                                    if (options.arrays || options.defaults)
+                                        object.detectedLanguages = [];
+                                    if (options.defaults)
+                                        object.layout = null;
+                                    if (message.layout != null && message.hasOwnProperty("layout"))
+                                        object.layout = $root.google.cloud.documentai.v1beta3.Document.Page.Layout.toObject(message.layout, options);
+                                    if (message.detectedLanguages && message.detectedLanguages.length) {
+                                        object.detectedLanguages = [];
+                                        for (var j = 0; j < message.detectedLanguages.length; ++j)
+                                            object.detectedLanguages[j] = $root.google.cloud.documentai.v1beta3.Document.Page.DetectedLanguage.toObject(message.detectedLanguages[j], options);
+                                    }
+                                    return object;
+                                };
+    
+                                /**
+                                 * Converts this Symbol to JSON.
+                                 * @function toJSON
+                                 * @memberof google.cloud.documentai.v1beta3.Document.Page.Symbol
+                                 * @instance
+                                 * @returns {Object.<string,*>} JSON object
+                                 */
+                                Symbol.prototype.toJSON = function toJSON() {
+                                    return this.constructor.toObject(this, $protobuf.util.toJSONOptions);
+                                };
+    
+                                return Symbol;
+                            })();
+    
                             Page.VisualElement = (function() {
     
                                 /**
@@ -56305,32 +56863,6 @@
              */
             var api = {};
     
-            /**
-             * FieldBehavior enum.
-             * @name google.api.FieldBehavior
-             * @enum {number}
-             * @property {number} FIELD_BEHAVIOR_UNSPECIFIED=0 FIELD_BEHAVIOR_UNSPECIFIED value
-             * @property {number} OPTIONAL=1 OPTIONAL value
-             * @property {number} REQUIRED=2 REQUIRED value
-             * @property {number} OUTPUT_ONLY=3 OUTPUT_ONLY value
-             * @property {number} INPUT_ONLY=4 INPUT_ONLY value
-             * @property {number} IMMUTABLE=5 IMMUTABLE value
-             * @property {number} UNORDERED_LIST=6 UNORDERED_LIST value
-             * @property {number} NON_EMPTY_DEFAULT=7 NON_EMPTY_DEFAULT value
-             */
-            api.FieldBehavior = (function() {
-                var valuesById = {}, values = Object.create(valuesById);
-                values[valuesById[0] = "FIELD_BEHAVIOR_UNSPECIFIED"] = 0;
-                values[valuesById[1] = "OPTIONAL"] = 1;
-                values[valuesById[2] = "REQUIRED"] = 2;
-                values[valuesById[3] = "OUTPUT_ONLY"] = 3;
-                values[valuesById[4] = "INPUT_ONLY"] = 4;
-                values[valuesById[5] = "IMMUTABLE"] = 5;
-                values[valuesById[6] = "UNORDERED_LIST"] = 6;
-                values[valuesById[7] = "NON_EMPTY_DEFAULT"] = 7;
-                return values;
-            })();
-    
             api.Http = (function() {
     
                 /**
@@ -57235,6 +57767,32 @@
                 return CustomHttpPattern;
             })();
     
+            /**
+             * FieldBehavior enum.
+             * @name google.api.FieldBehavior
+             * @enum {number}
+             * @property {number} FIELD_BEHAVIOR_UNSPECIFIED=0 FIELD_BEHAVIOR_UNSPECIFIED value
+             * @property {number} OPTIONAL=1 OPTIONAL value
+             * @property {number} REQUIRED=2 REQUIRED value
+             * @property {number} OUTPUT_ONLY=3 OUTPUT_ONLY value
+             * @property {number} INPUT_ONLY=4 INPUT_ONLY value
+             * @property {number} IMMUTABLE=5 IMMUTABLE value
+             * @property {number} UNORDERED_LIST=6 UNORDERED_LIST value
+             * @property {number} NON_EMPTY_DEFAULT=7 NON_EMPTY_DEFAULT value
+             */
+            api.FieldBehavior = (function() {
+                var valuesById = {}, values = Object.create(valuesById);
+                values[valuesById[0] = "FIELD_BEHAVIOR_UNSPECIFIED"] = 0;
+                values[valuesById[1] = "OPTIONAL"] = 1;
+                values[valuesById[2] = "REQUIRED"] = 2;
+                values[valuesById[3] = "OUTPUT_ONLY"] = 3;
+                values[valuesById[4] = "INPUT_ONLY"] = 4;
+                values[valuesById[5] = "IMMUTABLE"] = 5;
+                values[valuesById[6] = "UNORDERED_LIST"] = 6;
+                values[valuesById[7] = "NON_EMPTY_DEFAULT"] = 7;
+                return values;
+            })();
+    
             api.ResourceDescriptor = (function() {
     
                 /**
diff --git a/protos/protos.json b/protos/protos.json
index 9ccf231fb..d24ee7e24 100644
--- a/protos/protos.json
+++ b/protos/protos.json
@@ -219,6 +219,11 @@
                               "type": "FormField",
                               "id": 11
                             },
+                            "symbols": {
+                              "rule": "repeated",
+                              "type": "Symbol",
+                              "id": 12
+                            },
                             "provenance": {
                               "type": "Provenance",
                               "id": 16
@@ -404,6 +409,19 @@
                                 }
                               }
                             },
+                            "Symbol": {
+                              "fields": {
+                                "layout": {
+                                  "type": "Layout",
+                                  "id": 1
+                                },
+                                "detectedLanguages": {
+                                  "rule": "repeated",
+                                  "type": "DetectedLanguage",
+                                  "id": 2
+                                }
+                              }
+                            },
                             "VisualElement": {
                               "fields": {
                                 "layout": {
@@ -636,7 +654,7 @@
                                   "type": "string",
                                   "id": 1,
                                   "options": {
-                                    "(google.api.field_behavior)": "REQUIRED"
+                                    "(google.api.field_behavior)": "OPTIONAL"
                                   }
                                 }
                               }
@@ -3369,6 +3387,11 @@
                               "type": "FormField",
                               "id": 11
                             },
+                            "symbols": {
+                              "rule": "repeated",
+                              "type": "Symbol",
+                              "id": 12
+                            },
                             "provenance": {
                               "type": "Provenance",
                               "id": 16
@@ -3554,6 +3577,19 @@
                                 }
                               }
                             },
+                            "Symbol": {
+                              "fields": {
+                                "layout": {
+                                  "type": "Layout",
+                                  "id": 1
+                                },
+                                "detectedLanguages": {
+                                  "rule": "repeated",
+                                  "type": "DetectedLanguage",
+                                  "id": 2
+                                }
+                              }
+                            },
                             "VisualElement": {
                               "fields": {
                                 "layout": {
@@ -3786,7 +3822,7 @@
                                   "type": "string",
                                   "id": 1,
                                   "options": {
-                                    "(google.api.field_behavior)": "REQUIRED"
+                                    "(google.api.field_behavior)": "OPTIONAL"
                                   }
                                 }
                               }
@@ -4968,24 +5004,6 @@
             "cc_enable_arenas": true
           },
           "nested": {
-            "fieldBehavior": {
-              "rule": "repeated",
-              "type": "google.api.FieldBehavior",
-              "id": 1052,
-              "extend": "google.protobuf.FieldOptions"
-            },
-            "FieldBehavior": {
-              "values": {
-                "FIELD_BEHAVIOR_UNSPECIFIED": 0,
-                "OPTIONAL": 1,
-                "REQUIRED": 2,
-                "OUTPUT_ONLY": 3,
-                "INPUT_ONLY": 4,
-                "IMMUTABLE": 5,
-                "UNORDERED_LIST": 6,
-                "NON_EMPTY_DEFAULT": 7
-              }
-            },
             "http": {
               "type": "HttpRule",
               "id": 72295728,
@@ -5073,6 +5091,24 @@
                 }
               }
             },
+            "fieldBehavior": {
+              "rule": "repeated",
+              "type": "google.api.FieldBehavior",
+              "id": 1052,
+              "extend": "google.protobuf.FieldOptions"
+            },
+            "FieldBehavior": {
+              "values": {
+                "FIELD_BEHAVIOR_UNSPECIFIED": 0,
+                "OPTIONAL": 1,
+                "REQUIRED": 2,
+                "OUTPUT_ONLY": 3,
+                "INPUT_ONLY": 4,
+                "IMMUTABLE": 5,
+                "UNORDERED_LIST": 6,
+                "NON_EMPTY_DEFAULT": 7
+              }
+            },
             "methodSignature": {
               "rule": "repeated",
               "type": "string",
diff --git a/samples/generated/v1/document_processor_service.batch_process_documents.js b/samples/generated/v1/document_processor_service.batch_process_documents.js
index 6651cd4d8..33e8eef0f 100644
--- a/samples/generated/v1/document_processor_service.batch_process_documents.js
+++ b/samples/generated/v1/document_processor_service.batch_process_documents.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1/document_processor_service.process_document.js b/samples/generated/v1/document_processor_service.process_document.js
index 849d86196..1ff38d5a9 100644
--- a/samples/generated/v1/document_processor_service.process_document.js
+++ b/samples/generated/v1/document_processor_service.process_document.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1/document_processor_service.review_document.js b/samples/generated/v1/document_processor_service.review_document.js
index 3ced01432..d78861aae 100644
--- a/samples/generated/v1/document_processor_service.review_document.js
+++ b/samples/generated/v1/document_processor_service.review_document.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1/snippet_metadata.google.cloud.documentai.v1.json b/samples/generated/v1/snippet_metadata.google.cloud.documentai.v1.json
new file mode 100644
index 000000000..1d4eabaf9
--- /dev/null
+++ b/samples/generated/v1/snippet_metadata.google.cloud.documentai.v1.json
@@ -0,0 +1,171 @@
+{
+  "clientLibrary": {
+    "name": "nodejs-documentai",
+    "version": "0.1.0",
+    "language": "TYPESCRIPT",
+    "apis": [
+      {
+        "id": "google.cloud.documentai.v1",
+        "version": "v1"
+      }
+    ]
+  },
+  "snippets": [
+    {
+      "regionTag": "documentai_v1_generated_DocumentProcessorService_ProcessDocument_async",
+      "title": "DocumentProcessorService processDocument Sample",
+      "origin": "API_DEFINITION",
+      "description": " Processes a single document.",
+      "canonical": true,
+      "file": "document_processor_service.process_document.js",
+      "language": "JAVASCRIPT",
+      "segments": [
+        {
+          "start": 25,
+          "end": 63,
+          "type": "FULL"
+        }
+      ],
+      "clientMethod": {
+        "shortName": "ProcessDocument",
+        "fullName": "google.cloud.documentai.v1.DocumentProcessorService.ProcessDocument",
+        "async": true,
+        "parameters": [
+          {
+            "name": "inline_document",
+            "type": ".google.cloud.documentai.v1.Document"
+          },
+          {
+            "name": "raw_document",
+            "type": ".google.cloud.documentai.v1.RawDocument"
+          },
+          {
+            "name": "name",
+            "type": "TYPE_STRING"
+          },
+          {
+            "name": "skip_human_review",
+            "type": "TYPE_BOOL"
+          }
+        ],
+        "resultType": ".google.cloud.documentai.v1.ProcessResponse",
+        "client": {
+          "shortName": "DocumentProcessorServiceClient",
+          "fullName": "google.cloud.documentai.v1.DocumentProcessorServiceClient"
+        },
+        "method": {
+          "shortName": "ProcessDocument",
+          "fullName": "google.cloud.documentai.v1.DocumentProcessorService.ProcessDocument",
+          "service": {
+            "shortName": "DocumentProcessorService",
+            "fullName": "google.cloud.documentai.v1.DocumentProcessorService"
+          }
+        }
+      }
+    },
+    {
+      "regionTag": "documentai_v1_generated_DocumentProcessorService_BatchProcessDocuments_async",
+      "title": "DocumentProcessorService batchProcessDocuments Sample",
+      "origin": "API_DEFINITION",
+      "description": " LRO endpoint to batch process many documents. The output is written to Cloud Storage as JSON in the [Document] format.",
+      "canonical": true,
+      "file": "document_processor_service.batch_process_documents.js",
+      "language": "JAVASCRIPT",
+      "segments": [
+        {
+          "start": 25,
+          "end": 64,
+          "type": "FULL"
+        }
+      ],
+      "clientMethod": {
+        "shortName": "BatchProcessDocuments",
+        "fullName": "google.cloud.documentai.v1.DocumentProcessorService.BatchProcessDocuments",
+        "async": true,
+        "parameters": [
+          {
+            "name": "name",
+            "type": "TYPE_STRING"
+          },
+          {
+            "name": "input_documents",
+            "type": ".google.cloud.documentai.v1.BatchDocumentsInputConfig"
+          },
+          {
+            "name": "document_output_config",
+            "type": ".google.cloud.documentai.v1.DocumentOutputConfig"
+          },
+          {
+            "name": "skip_human_review",
+            "type": "TYPE_BOOL"
+          }
+        ],
+        "resultType": ".google.longrunning.Operation",
+        "client": {
+          "shortName": "DocumentProcessorServiceClient",
+          "fullName": "google.cloud.documentai.v1.DocumentProcessorServiceClient"
+        },
+        "method": {
+          "shortName": "BatchProcessDocuments",
+          "fullName": "google.cloud.documentai.v1.DocumentProcessorService.BatchProcessDocuments",
+          "service": {
+            "shortName": "DocumentProcessorService",
+            "fullName": "google.cloud.documentai.v1.DocumentProcessorService"
+          }
+        }
+      }
+    },
+    {
+      "regionTag": "documentai_v1_generated_DocumentProcessorService_ReviewDocument_async",
+      "title": "DocumentProcessorService reviewDocument Sample",
+      "origin": "API_DEFINITION",
+      "description": " Send a document for Human Review. The input document should be processed by the specified processor.",
+      "canonical": true,
+      "file": "document_processor_service.review_document.js",
+      "language": "JAVASCRIPT",
+      "segments": [
+        {
+          "start": 25,
+          "end": 64,
+          "type": "FULL"
+        }
+      ],
+      "clientMethod": {
+        "shortName": "ReviewDocument",
+        "fullName": "google.cloud.documentai.v1.DocumentProcessorService.ReviewDocument",
+        "async": true,
+        "parameters": [
+          {
+            "name": "inline_document",
+            "type": ".google.cloud.documentai.v1.Document"
+          },
+          {
+            "name": "human_review_config",
+            "type": "TYPE_STRING"
+          },
+          {
+            "name": "enable_schema_validation",
+            "type": "TYPE_BOOL"
+          },
+          {
+            "name": "priority",
+            "type": ".google.cloud.documentai.v1.ReviewDocumentRequest.Priority"
+          }
+        ],
+        "resultType": ".google.longrunning.Operation",
+        "client": {
+          "shortName": "DocumentProcessorServiceClient",
+          "fullName": "google.cloud.documentai.v1.DocumentProcessorServiceClient"
+        },
+        "method": {
+          "shortName": "ReviewDocument",
+          "fullName": "google.cloud.documentai.v1.DocumentProcessorService.ReviewDocument",
+          "service": {
+            "shortName": "DocumentProcessorService",
+            "fullName": "google.cloud.documentai.v1.DocumentProcessorService"
+          }
+        }
+      }
+    }
+  ]
+}
diff --git a/samples/generated/v1beta1/document_understanding_service.batch_process_documents.js b/samples/generated/v1beta1/document_understanding_service.batch_process_documents.js
index 4e9d54da9..b521d8f8f 100644
--- a/samples/generated/v1beta1/document_understanding_service.batch_process_documents.js
+++ b/samples/generated/v1beta1/document_understanding_service.batch_process_documents.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta1/snippet_metadata.google.cloud.documentai.v1beta1.json b/samples/generated/v1beta1/snippet_metadata.google.cloud.documentai.v1beta1.json
new file mode 100644
index 000000000..6fb76dcd0
--- /dev/null
+++ b/samples/generated/v1beta1/snippet_metadata.google.cloud.documentai.v1beta1.json
@@ -0,0 +1,59 @@
+{
+  "clientLibrary": {
+    "name": "nodejs-documentai",
+    "version": "0.1.0",
+    "language": "TYPESCRIPT",
+    "apis": [
+      {
+        "id": "google.cloud.documentai.v1beta1",
+        "version": "v1beta1"
+      }
+    ]
+  },
+  "snippets": [
+    {
+      "regionTag": "documentai_v1beta1_generated_DocumentUnderstandingService_BatchProcessDocuments_async",
+      "title": "DocumentUnderstandingService batchProcessDocuments Sample",
+      "origin": "API_DEFINITION",
+      "description": " LRO endpoint to batch process many documents.",
+      "canonical": true,
+      "file": "document_understanding_service.batch_process_documents.js",
+      "language": "JAVASCRIPT",
+      "segments": [
+        {
+          "start": 25,
+          "end": 57,
+          "type": "FULL"
+        }
+      ],
+      "clientMethod": {
+        "shortName": "BatchProcessDocuments",
+        "fullName": "google.cloud.documentai.v1beta1.DocumentUnderstandingService.BatchProcessDocuments",
+        "async": true,
+        "parameters": [
+          {
+            "name": "requests",
+            "type": "TYPE_MESSAGE[]"
+          },
+          {
+            "name": "parent",
+            "type": "TYPE_STRING"
+          }
+        ],
+        "resultType": ".google.longrunning.Operation",
+        "client": {
+          "shortName": "DocumentUnderstandingServiceClient",
+          "fullName": "google.cloud.documentai.v1beta1.DocumentUnderstandingServiceClient"
+        },
+        "method": {
+          "shortName": "BatchProcessDocuments",
+          "fullName": "google.cloud.documentai.v1beta1.DocumentUnderstandingService.BatchProcessDocuments",
+          "service": {
+            "shortName": "DocumentUnderstandingService",
+            "fullName": "google.cloud.documentai.v1beta1.DocumentUnderstandingService"
+          }
+        }
+      }
+    }
+  ]
+}
diff --git a/samples/generated/v1beta2/document_understanding_service.batch_process_documents.js b/samples/generated/v1beta2/document_understanding_service.batch_process_documents.js
index ad7d7d1e1..8b2ab19f5 100644
--- a/samples/generated/v1beta2/document_understanding_service.batch_process_documents.js
+++ b/samples/generated/v1beta2/document_understanding_service.batch_process_documents.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta2/document_understanding_service.process_document.js b/samples/generated/v1beta2/document_understanding_service.process_document.js
index 5864d9937..f689731c7 100644
--- a/samples/generated/v1beta2/document_understanding_service.process_document.js
+++ b/samples/generated/v1beta2/document_understanding_service.process_document.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta2/snippet_metadata.google.cloud.documentai.v1beta2.json b/samples/generated/v1beta2/snippet_metadata.google.cloud.documentai.v1beta2.json
new file mode 100644
index 000000000..ad1852149
--- /dev/null
+++ b/samples/generated/v1beta2/snippet_metadata.google.cloud.documentai.v1beta2.json
@@ -0,0 +1,131 @@
+{
+  "clientLibrary": {
+    "name": "nodejs-documentai",
+    "version": "0.1.0",
+    "language": "TYPESCRIPT",
+    "apis": [
+      {
+        "id": "google.cloud.documentai.v1beta2",
+        "version": "v1beta2"
+      }
+    ]
+  },
+  "snippets": [
+    {
+      "regionTag": "documentai_v1beta2_generated_DocumentUnderstandingService_BatchProcessDocuments_async",
+      "title": "DocumentUnderstandingService batchProcessDocuments Sample",
+      "origin": "API_DEFINITION",
+      "description": " LRO endpoint to batch process many documents. The output is written to Cloud Storage as JSON in the [Document] format.",
+      "canonical": true,
+      "file": "document_understanding_service.batch_process_documents.js",
+      "language": "JAVASCRIPT",
+      "segments": [
+        {
+          "start": 25,
+          "end": 57,
+          "type": "FULL"
+        }
+      ],
+      "clientMethod": {
+        "shortName": "BatchProcessDocuments",
+        "fullName": "google.cloud.documentai.v1beta2.DocumentUnderstandingService.BatchProcessDocuments",
+        "async": true,
+        "parameters": [
+          {
+            "name": "requests",
+            "type": "TYPE_MESSAGE[]"
+          },
+          {
+            "name": "parent",
+            "type": "TYPE_STRING"
+          }
+        ],
+        "resultType": ".google.longrunning.Operation",
+        "client": {
+          "shortName": "DocumentUnderstandingServiceClient",
+          "fullName": "google.cloud.documentai.v1beta2.DocumentUnderstandingServiceClient"
+        },
+        "method": {
+          "shortName": "BatchProcessDocuments",
+          "fullName": "google.cloud.documentai.v1beta2.DocumentUnderstandingService.BatchProcessDocuments",
+          "service": {
+            "shortName": "DocumentUnderstandingService",
+            "fullName": "google.cloud.documentai.v1beta2.DocumentUnderstandingService"
+          }
+        }
+      }
+    },
+    {
+      "regionTag": "documentai_v1beta2_generated_DocumentUnderstandingService_ProcessDocument_async",
+      "title": "DocumentUnderstandingService processDocument Sample",
+      "origin": "API_DEFINITION",
+      "description": " Processes a single document.",
+      "canonical": true,
+      "file": "document_understanding_service.process_document.js",
+      "language": "JAVASCRIPT",
+      "segments": [
+        {
+          "start": 25,
+          "end": 93,
+          "type": "FULL"
+        }
+      ],
+      "clientMethod": {
+        "shortName": "ProcessDocument",
+        "fullName": "google.cloud.documentai.v1beta2.DocumentUnderstandingService.ProcessDocument",
+        "async": true,
+        "parameters": [
+          {
+            "name": "parent",
+            "type": "TYPE_STRING"
+          },
+          {
+            "name": "input_config",
+            "type": ".google.cloud.documentai.v1beta2.InputConfig"
+          },
+          {
+            "name": "output_config",
+            "type": ".google.cloud.documentai.v1beta2.OutputConfig"
+          },
+          {
+            "name": "document_type",
+            "type": "TYPE_STRING"
+          },
+          {
+            "name": "table_extraction_params",
+            "type": ".google.cloud.documentai.v1beta2.TableExtractionParams"
+          },
+          {
+            "name": "form_extraction_params",
+            "type": ".google.cloud.documentai.v1beta2.FormExtractionParams"
+          },
+          {
+            "name": "entity_extraction_params",
+            "type": ".google.cloud.documentai.v1beta2.EntityExtractionParams"
+          },
+          {
+            "name": "ocr_params",
+            "type": ".google.cloud.documentai.v1beta2.OcrParams"
+          },
+          {
+            "name": "automl_params",
+            "type": ".google.cloud.documentai.v1beta2.AutoMlParams"
+          }
+        ],
+        "resultType": ".google.cloud.documentai.v1beta2.Document",
+        "client": {
+          "shortName": "DocumentUnderstandingServiceClient",
+          "fullName": "google.cloud.documentai.v1beta2.DocumentUnderstandingServiceClient"
+        },
+        "method": {
+          "shortName": "ProcessDocument",
+          "fullName": "google.cloud.documentai.v1beta2.DocumentUnderstandingService.ProcessDocument",
+          "service": {
+            "shortName": "DocumentUnderstandingService",
+            "fullName": "google.cloud.documentai.v1beta2.DocumentUnderstandingService"
+          }
+        }
+      }
+    }
+  ]
+}
diff --git a/samples/generated/v1beta3/document_processor_service.batch_process_documents.js b/samples/generated/v1beta3/document_processor_service.batch_process_documents.js
index 596ffb8e7..65ed20475 100644
--- a/samples/generated/v1beta3/document_processor_service.batch_process_documents.js
+++ b/samples/generated/v1beta3/document_processor_service.batch_process_documents.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta3/document_processor_service.create_processor.js b/samples/generated/v1beta3/document_processor_service.create_processor.js
index cedc57901..6fa2b2766 100644
--- a/samples/generated/v1beta3/document_processor_service.create_processor.js
+++ b/samples/generated/v1beta3/document_processor_service.create_processor.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta3/document_processor_service.delete_processor.js b/samples/generated/v1beta3/document_processor_service.delete_processor.js
index 3b20ac69a..23228e139 100644
--- a/samples/generated/v1beta3/document_processor_service.delete_processor.js
+++ b/samples/generated/v1beta3/document_processor_service.delete_processor.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta3/document_processor_service.disable_processor.js b/samples/generated/v1beta3/document_processor_service.disable_processor.js
index b6bbe5af0..219f687ea 100644
--- a/samples/generated/v1beta3/document_processor_service.disable_processor.js
+++ b/samples/generated/v1beta3/document_processor_service.disable_processor.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta3/document_processor_service.enable_processor.js b/samples/generated/v1beta3/document_processor_service.enable_processor.js
index 32f84b4da..88e78e8d9 100644
--- a/samples/generated/v1beta3/document_processor_service.enable_processor.js
+++ b/samples/generated/v1beta3/document_processor_service.enable_processor.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta3/document_processor_service.fetch_processor_types.js b/samples/generated/v1beta3/document_processor_service.fetch_processor_types.js
index ad17c02ad..c0c9b717e 100644
--- a/samples/generated/v1beta3/document_processor_service.fetch_processor_types.js
+++ b/samples/generated/v1beta3/document_processor_service.fetch_processor_types.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta3/document_processor_service.list_processors.js b/samples/generated/v1beta3/document_processor_service.list_processors.js
index 0e7a5e8d1..cfea7fd67 100644
--- a/samples/generated/v1beta3/document_processor_service.list_processors.js
+++ b/samples/generated/v1beta3/document_processor_service.list_processors.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta3/document_processor_service.process_document.js b/samples/generated/v1beta3/document_processor_service.process_document.js
index 112ef1e6b..2c0d6e90f 100644
--- a/samples/generated/v1beta3/document_processor_service.process_document.js
+++ b/samples/generated/v1beta3/document_processor_service.process_document.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta3/document_processor_service.review_document.js b/samples/generated/v1beta3/document_processor_service.review_document.js
index fc4ee4528..fd35938f6 100644
--- a/samples/generated/v1beta3/document_processor_service.review_document.js
+++ b/samples/generated/v1beta3/document_processor_service.review_document.js
@@ -1,16 +1,21 @@
-// Copyright 2021 Google LLC
+// Copyright 2022 Google LLC
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
-//      http://www.apache.org/licenses/LICENSE-2.0
+//     https://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
+//
+// ** This file is automatically generated by gapic-generator-typescript. **
+// ** https://github.com/googleapis/gapic-generator-typescript **
+// ** All changes to this file may be overwritten. **
+
 
 
 'use strict';
diff --git a/samples/generated/v1beta3/snippet_metadata.google.cloud.documentai.v1beta3.json b/samples/generated/v1beta3/snippet_metadata.google.cloud.documentai.v1beta3.json
new file mode 100644
index 000000000..fc76128ab
--- /dev/null
+++ b/samples/generated/v1beta3/snippet_metadata.google.cloud.documentai.v1beta3.json
@@ -0,0 +1,439 @@
+{
+  "clientLibrary": {
+    "name": "nodejs-documentai",
+    "version": "0.1.0",
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+        "version": "v1beta3"
+      }
+    ]
+  },
+  "snippets": [
+    {
+      "regionTag": "documentai_v1beta3_generated_DocumentProcessorService_ProcessDocument_async",
+      "title": "DocumentProcessorService processDocument Sample",
+      "origin": "API_DEFINITION",
+      "description": " Processes a single document.",
+      "canonical": true,
+      "file": "document_processor_service.process_document.js",
+      "language": "JAVASCRIPT",
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+        }
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+        "fullName": "google.cloud.documentai.v1beta3.DocumentProcessorService.ProcessDocument",
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+            "name": "inline_document",
+            "type": ".google.cloud.documentai.v1beta3.Document"
+          },
+          {
+            "name": "raw_document",
+            "type": ".google.cloud.documentai.v1beta3.RawDocument"
+          },
+          {
+            "name": "name",
+            "type": "TYPE_STRING"
+          },
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+          {
+            "name": "skip_human_review",
+            "type": "TYPE_BOOL"
+          }
+        ],
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+      }
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+    {
+      "regionTag": "documentai_v1beta3_generated_DocumentProcessorService_BatchProcessDocuments_async",
+      "title": "DocumentProcessorService batchProcessDocuments Sample",
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+      "description": " LRO endpoint to batch process many documents. The output is written to Cloud Storage as JSON in the [Document] format.",
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+          {
+            "name": "input_configs",
+            "type": "TYPE_MESSAGE[]"
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+            "type": ".google.cloud.documentai.v1beta3.BatchDocumentsInputConfig"
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+          {
+            "name": "document_output_config",
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+      "canonical": true,
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+            "type": "TYPE_STRING"
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+        }
+      }
+    },
+    {
+      "regionTag": "documentai_v1beta3_generated_DocumentProcessorService_ListProcessors_async",
+      "title": "DocumentProcessorService listProcessors Sample",
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+      "description": " Lists all processors which belong to this project.",
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+        "fullName": "google.cloud.documentai.v1beta3.DocumentProcessorService.ListProcessors",
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+            "name": "parent",
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+      "description": " Creates a processor from the type processor that the user chose. The processor will be at \"ENABLED\" state by default after its creation.",
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+      "origin": "API_DEFINITION",
+      "description": " Deletes the processor, unloads all deployed model artifacts if it was enabled and then deletes all artifacts associated with this processor.",
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+    },
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+      "title": "DocumentProcessorService reviewDocument Sample",
+      "origin": "API_DEFINITION",
+      "description": " Send a document for Human Review. The input document should be processed by the specified processor.",
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+      "file": "document_processor_service.review_document.js",
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+      "clientMethod": {
+        "shortName": "ReviewDocument",
+        "fullName": "google.cloud.documentai.v1beta3.DocumentProcessorService.ReviewDocument",
+        "async": true,
+        "parameters": [
+          {
+            "name": "inline_document",
+            "type": ".google.cloud.documentai.v1beta3.Document"
+          },
+          {
+            "name": "human_review_config",
+            "type": "TYPE_STRING"
+          },
+          {
+            "name": "document",
+            "type": ".google.cloud.documentai.v1beta3.Document"
+          },
+          {
+            "name": "enable_schema_validation",
+            "type": "TYPE_BOOL"
+          },
+          {
+            "name": "priority",
+            "type": ".google.cloud.documentai.v1beta3.ReviewDocumentRequest.Priority"
+          }
+        ],
+        "resultType": ".google.longrunning.Operation",
+        "client": {
+          "shortName": "DocumentProcessorServiceClient",
+          "fullName": "google.cloud.documentai.v1beta3.DocumentProcessorServiceClient"
+        },
+        "method": {
+          "shortName": "ReviewDocument",
+          "fullName": "google.cloud.documentai.v1beta3.DocumentProcessorService.ReviewDocument",
+          "service": {
+            "shortName": "DocumentProcessorService",
+            "fullName": "google.cloud.documentai.v1beta3.DocumentProcessorService"
+          }
+        }
+      }
+    }
+  ]
+}
diff --git a/src/v1/document_processor_service_client.ts b/src/v1/document_processor_service_client.ts
index 794cc921c..038d6c11d 100644
--- a/src/v1/document_processor_service_client.ts
+++ b/src/v1/document_processor_service_client.ts
@@ -844,9 +844,8 @@ export class DocumentProcessorServiceClient {
    * @returns {Promise} A promise that resolves when the client is closed.
    */
   close(): Promise<void> {
-    this.initialize();
-    if (!this._terminated) {
-      return this.documentProcessorServiceStub!.then(stub => {
+    if (this.documentProcessorServiceStub && !this._terminated) {
+      return this.documentProcessorServiceStub.then(stub => {
         this._terminated = true;
         stub.close();
         this.operationsClient.close();
diff --git a/src/v1beta1/document_understanding_service_client.ts b/src/v1beta1/document_understanding_service_client.ts
index 4135b2201..238a9b913 100644
--- a/src/v1beta1/document_understanding_service_client.ts
+++ b/src/v1beta1/document_understanding_service_client.ts
@@ -468,9 +468,8 @@ export class DocumentUnderstandingServiceClient {
    * @returns {Promise} A promise that resolves when the client is closed.
    */
   close(): Promise<void> {
-    this.initialize();
-    if (!this._terminated) {
-      return this.documentUnderstandingServiceStub!.then(stub => {
+    if (this.documentUnderstandingServiceStub && !this._terminated) {
+      return this.documentUnderstandingServiceStub.then(stub => {
         this._terminated = true;
         stub.close();
         this.operationsClient.close();
diff --git a/src/v1beta2/document_understanding_service_client.ts b/src/v1beta2/document_understanding_service_client.ts
index 8d24e78da..24c3cd2fa 100644
--- a/src/v1beta2/document_understanding_service_client.ts
+++ b/src/v1beta2/document_understanding_service_client.ts
@@ -598,9 +598,8 @@ export class DocumentUnderstandingServiceClient {
    * @returns {Promise} A promise that resolves when the client is closed.
    */
   close(): Promise<void> {
-    this.initialize();
-    if (!this._terminated) {
-      return this.documentUnderstandingServiceStub!.then(stub => {
+    if (this.documentUnderstandingServiceStub && !this._terminated) {
+      return this.documentUnderstandingServiceStub.then(stub => {
         this._terminated = true;
         stub.close();
         this.operationsClient.close();
diff --git a/src/v1beta3/document_processor_service_client.ts b/src/v1beta3/document_processor_service_client.ts
index d9f6bcf37..0d5704520 100644
--- a/src/v1beta3/document_processor_service_client.ts
+++ b/src/v1beta3/document_processor_service_client.ts
@@ -1844,9 +1844,8 @@ export class DocumentProcessorServiceClient {
    * @returns {Promise} A promise that resolves when the client is closed.
    */
   close(): Promise<void> {
-    this.initialize();
-    if (!this._terminated) {
-      return this.documentProcessorServiceStub!.then(stub => {
+    if (this.documentProcessorServiceStub && !this._terminated) {
+      return this.documentProcessorServiceStub.then(stub => {
         this._terminated = true;
         stub.close();
         this.operationsClient.close();
diff --git a/test/gapic_document_processor_service_v1.ts b/test/gapic_document_processor_service_v1.ts
index 4c9a793a3..79ba37f22 100644
--- a/test/gapic_document_processor_service_v1.ts
+++ b/test/gapic_document_processor_service_v1.ts
@@ -128,13 +128,29 @@ describe('v1.DocumentProcessorServiceClient', () => {
     assert(client.documentProcessorServiceStub);
   });
 
-  it('has close method', () => {
+  it('has close method for the initialized client', done => {
     const client =
       new documentprocessorserviceModule.v1.DocumentProcessorServiceClient({
         credentials: {client_email: 'bogus', private_key: 'bogus'},
         projectId: 'bogus',
       });
-    client.close();
+    client.initialize();
+    assert(client.documentProcessorServiceStub);
+    client.close().then(() => {
+      done();
+    });
+  });
+
+  it('has close method for the non-initialized client', done => {
+    const client =
+      new documentprocessorserviceModule.v1.DocumentProcessorServiceClient({
+        credentials: {client_email: 'bogus', private_key: 'bogus'},
+        projectId: 'bogus',
+      });
+    assert.strictEqual(client.documentProcessorServiceStub, undefined);
+    client.close().then(() => {
+      done();
+    });
   });
 
   it('has getProjectId method', async () => {
@@ -285,6 +301,23 @@ describe('v1.DocumentProcessorServiceClient', () => {
           .calledWith(request, expectedOptions, undefined)
       );
     });
+
+    it('invokes processDocument with closed client', async () => {
+      const client =
+        new documentprocessorserviceModule.v1.DocumentProcessorServiceClient({
+          credentials: {client_email: 'bogus', private_key: 'bogus'},
+          projectId: 'bogus',
+        });
+      client.initialize();
+      const request = generateSampleMessage(
+        new protos.google.cloud.documentai.v1.ProcessRequest()
+      );
+      request.name = '';
+      const expectedHeaderRequestParams = 'name=';
+      const expectedError = new Error('The client has already been closed.');
+      client.close();
+      await assert.rejects(client.processDocument(request), expectedError);
+    });
   });
 
   describe('batchProcessDocuments', () => {
diff --git a/test/gapic_document_processor_service_v1beta3.ts b/test/gapic_document_processor_service_v1beta3.ts
index 377013c94..438415632 100644
--- a/test/gapic_document_processor_service_v1beta3.ts
+++ b/test/gapic_document_processor_service_v1beta3.ts
@@ -196,7 +196,7 @@ describe('v1beta3.DocumentProcessorServiceClient', () => {
     assert(client.documentProcessorServiceStub);
   });
 
-  it('has close method', () => {
+  it('has close method for the initialized client', done => {
     const client =
       new documentprocessorserviceModule.v1beta3.DocumentProcessorServiceClient(
         {
@@ -204,7 +204,25 @@ describe('v1beta3.DocumentProcessorServiceClient', () => {
           projectId: 'bogus',
         }
       );
-    client.close();
+    client.initialize();
+    assert(client.documentProcessorServiceStub);
+    client.close().then(() => {
+      done();
+    });
+  });
+
+  it('has close method for the non-initialized client', done => {
+    const client =
+      new documentprocessorserviceModule.v1beta3.DocumentProcessorServiceClient(
+        {
+          credentials: {client_email: 'bogus', private_key: 'bogus'},
+          projectId: 'bogus',
+        }
+      );
+    assert.strictEqual(client.documentProcessorServiceStub, undefined);
+    client.close().then(() => {
+      done();
+    });
   });
 
   it('has getProjectId method', async () => {
@@ -365,6 +383,25 @@ describe('v1beta3.DocumentProcessorServiceClient', () => {
           .calledWith(request, expectedOptions, undefined)
       );
     });
+
+    it('invokes processDocument with closed client', async () => {
+      const client =
+        new documentprocessorserviceModule.v1beta3.DocumentProcessorServiceClient(
+          {
+            credentials: {client_email: 'bogus', private_key: 'bogus'},
+            projectId: 'bogus',
+          }
+        );
+      client.initialize();
+      const request = generateSampleMessage(
+        new protos.google.cloud.documentai.v1beta3.ProcessRequest()
+      );
+      request.name = '';
+      const expectedHeaderRequestParams = 'name=';
+      const expectedError = new Error('The client has already been closed.');
+      client.close();
+      await assert.rejects(client.processDocument(request), expectedError);
+    });
   });
 
   describe('fetchProcessorTypes', () => {
@@ -486,6 +523,25 @@ describe('v1beta3.DocumentProcessorServiceClient', () => {
           .calledWith(request, expectedOptions, undefined)
       );
     });
+
+    it('invokes fetchProcessorTypes with closed client', async () => {
+      const client =
+        new documentprocessorserviceModule.v1beta3.DocumentProcessorServiceClient(
+          {
+            credentials: {client_email: 'bogus', private_key: 'bogus'},
+            projectId: 'bogus',
+          }
+        );
+      client.initialize();
+      const request = generateSampleMessage(
+        new protos.google.cloud.documentai.v1beta3.FetchProcessorTypesRequest()
+      );
+      request.parent = '';
+      const expectedHeaderRequestParams = 'parent=';
+      const expectedError = new Error('The client has already been closed.');
+      client.close();
+      await assert.rejects(client.fetchProcessorTypes(request), expectedError);
+    });
   });
 
   describe('createProcessor', () => {
@@ -606,6 +662,25 @@ describe('v1beta3.DocumentProcessorServiceClient', () => {
           .calledWith(request, expectedOptions, undefined)
       );
     });
+
+    it('invokes createProcessor with closed client', async () => {
+      const client =
+        new documentprocessorserviceModule.v1beta3.DocumentProcessorServiceClient(
+          {
+            credentials: {client_email: 'bogus', private_key: 'bogus'},
+            projectId: 'bogus',
+          }
+        );
+      client.initialize();
+      const request = generateSampleMessage(
+        new protos.google.cloud.documentai.v1beta3.CreateProcessorRequest()
+      );
+      request.parent = '';
+      const expectedHeaderRequestParams = 'parent=';
+      const expectedError = new Error('The client has already been closed.');
+      client.close();
+      await assert.rejects(client.createProcessor(request), expectedError);
+    });
   });
 
   describe('batchProcessDocuments', () => {
diff --git a/test/gapic_document_understanding_service_v1beta1.ts b/test/gapic_document_understanding_service_v1beta1.ts
index 90b5ea5dd..521250e72 100644
--- a/test/gapic_document_understanding_service_v1beta1.ts
+++ b/test/gapic_document_understanding_service_v1beta1.ts
@@ -124,7 +124,7 @@ describe('v1beta1.DocumentUnderstandingServiceClient', () => {
     assert(client.documentUnderstandingServiceStub);
   });
 
-  it('has close method', () => {
+  it('has close method for the initialized client', done => {
     const client =
       new documentunderstandingserviceModule.v1beta1.DocumentUnderstandingServiceClient(
         {
@@ -132,7 +132,25 @@ describe('v1beta1.DocumentUnderstandingServiceClient', () => {
           projectId: 'bogus',
         }
       );
-    client.close();
+    client.initialize();
+    assert(client.documentUnderstandingServiceStub);
+    client.close().then(() => {
+      done();
+    });
+  });
+
+  it('has close method for the non-initialized client', done => {
+    const client =
+      new documentunderstandingserviceModule.v1beta1.DocumentUnderstandingServiceClient(
+        {
+          credentials: {client_email: 'bogus', private_key: 'bogus'},
+          projectId: 'bogus',
+        }
+      );
+    assert.strictEqual(client.documentUnderstandingServiceStub, undefined);
+    client.close().then(() => {
+      done();
+    });
   });
 
   it('has getProjectId method', async () => {
diff --git a/test/gapic_document_understanding_service_v1beta2.ts b/test/gapic_document_understanding_service_v1beta2.ts
index c277620b8..e92cfd7d3 100644
--- a/test/gapic_document_understanding_service_v1beta2.ts
+++ b/test/gapic_document_understanding_service_v1beta2.ts
@@ -133,7 +133,7 @@ describe('v1beta2.DocumentUnderstandingServiceClient', () => {
     assert(client.documentUnderstandingServiceStub);
   });
 
-  it('has close method', () => {
+  it('has close method for the initialized client', done => {
     const client =
       new documentunderstandingserviceModule.v1beta2.DocumentUnderstandingServiceClient(
         {
@@ -141,7 +141,25 @@ describe('v1beta2.DocumentUnderstandingServiceClient', () => {
           projectId: 'bogus',
         }
       );
-    client.close();
+    client.initialize();
+    assert(client.documentUnderstandingServiceStub);
+    client.close().then(() => {
+      done();
+    });
+  });
+
+  it('has close method for the non-initialized client', done => {
+    const client =
+      new documentunderstandingserviceModule.v1beta2.DocumentUnderstandingServiceClient(
+        {
+          credentials: {client_email: 'bogus', private_key: 'bogus'},
+          projectId: 'bogus',
+        }
+      );
+    assert.strictEqual(client.documentUnderstandingServiceStub, undefined);
+    client.close().then(() => {
+      done();
+    });
   });
 
   it('has getProjectId method', async () => {
@@ -302,6 +320,25 @@ describe('v1beta2.DocumentUnderstandingServiceClient', () => {
           .calledWith(request, expectedOptions, undefined)
       );
     });
+
+    it('invokes processDocument with closed client', async () => {
+      const client =
+        new documentunderstandingserviceModule.v1beta2.DocumentUnderstandingServiceClient(
+          {
+            credentials: {client_email: 'bogus', private_key: 'bogus'},
+            projectId: 'bogus',
+          }
+        );
+      client.initialize();
+      const request = generateSampleMessage(
+        new protos.google.cloud.documentai.v1beta2.ProcessDocumentRequest()
+      );
+      request.parent = '';
+      const expectedHeaderRequestParams = 'parent=';
+      const expectedError = new Error('The client has already been closed.');
+      client.close();
+      await assert.rejects(client.processDocument(request), expectedError);
+    });
   });
 
   describe('batchProcessDocuments', () => {