diff --git a/packages/exo/test/test-legacy-guard-tolerance.js b/packages/exo/test/test-legacy-guard-tolerance.js
index d2377a2246..652cc4d1c1 100644
--- a/packages/exo/test/test-legacy-guard-tolerance.js
+++ b/packages/exo/test/test-legacy-guard-tolerance.js
@@ -49,9 +49,8 @@ test('legacy guard tolerance', async t => {
     argGuard: 88,
   });
   // @ts-expect-error Legacy adaptor can be ill typed
-  t.throws(() => getAwaitArgGuardPayload(laag), {
-    message:
-      'awaitArgGuard: copyRecord {"argGuard":88,"klass":"awaitArg"} - Must be a guard:awaitArgGuard',
+  t.deepEqual(getAwaitArgGuardPayload(laag), {
+    argGuard: 88,
   });
 
   t.deepEqual(getMethodGuardPayload(mg1), {
@@ -69,9 +68,12 @@ test('legacy guard tolerance', async t => {
     returnGuard: M.any(),
   });
   // @ts-expect-error Legacy adaptor can be ill typed
-  t.throws(() => getMethodGuardPayload(lmg), {
-    message:
-      'methodGuard: copyRecord {"argGuards":[77,{"argGuard":88,"klass":"awaitArg"}],"callKind":"async","klass":"methodGuard","returnGuard":"[match:any]"} - Must be a guard:methodGuard',
+  t.deepEqual(getMethodGuardPayload(lmg), {
+    callKind: 'async',
+    argGuards: [77, aag],
+    optionalArgGuards: undefined,
+    restArgGuard: undefined,
+    returnGuard: M.any(),
   });
 
   t.deepEqual(getInterfaceGuardPayload(ig1), {
@@ -97,9 +99,16 @@ test('legacy guard tolerance', async t => {
     },
   );
   // @ts-expect-error Legacy adaptor can be ill typed
-  t.throws(() => getInterfaceGuardPayload(lig), {
-    message:
-      'interfaceGuard: copyRecord {"interfaceName":"Foo","klass":"Interface","methodGuards":{"lmg":{"argGuards":[77,{"argGuard":88,"klass":"awaitArg"}],"callKind":"async","klass":"methodGuard","returnGuard":"[match:any]"},"mg1":"[guard:methodGuard]","mg2":"[guard:methodGuard]"}} - Must be a guard:interfaceGuard',
+  t.deepEqual(getInterfaceGuardPayload(lig), {
+    interfaceName: 'Foo',
+    methodGuards: {
+      mg1,
+      mg2,
+      lmg: M.callWhen(77, M.await(88))
+        .optional()
+        .rest(M.any())
+        .returns(M.any()),
+    },
   });
 
   const { meth } = {
@@ -121,20 +130,29 @@ test('legacy guard tolerance', async t => {
   });
   t.deepEqual(await f1.mg2(77, laag), [77, laag]);
 
-  t.throws(
-    () =>
-      makeExo(
-        'foo',
-        // @ts-expect-error Legacy adaptor can be ill typed
-        lig,
-        {
-          mg1: meth,
-          mg2: meth,
-        },
-      ),
+  const f2 = makeExo(
+    'foo',
+    // @ts-expect-error Legacy adaptor can be ill typed
+    lig,
     {
-      message:
-        'interfaceGuard: copyRecord {"interfaceName":"Foo","klass":"Interface","methodGuards":{"lmg":{"argGuards":[77,{"argGuard":88,"klass":"awaitArg"}],"callKind":"async","klass":"methodGuard","returnGuard":"[match:any]"},"mg1":"[guard:methodGuard]","mg2":"[guard:methodGuard]"}} - Must be a guard:interfaceGuard',
+      mg1: meth,
+      mg2: meth,
+      lmg: meth,
     },
   );
+  t.deepEqual(await f2.mg1(77, 88), [77, 88]);
+  await t.throwsAsync(async () => f2.mg1(77, laag), {
+    message:
+      'In "mg1" method of (foo): arg 1: {"argGuard":88,"klass":"awaitArg"} - Must be: 88',
+  });
+  await t.throwsAsync(async () => f2.mg2(77, 88), {
+    message:
+      'In "mg2" method of (foo): arg 1: 88 - Must be: {"argGuard":88,"klass":"awaitArg"}',
+  });
+  t.deepEqual(await f2.mg2(77, laag), [77, laag]);
+  t.deepEqual(await f2.lmg(77, 88), [77, 88]);
+  await t.throwsAsync(async () => f2.lmg(77, laag), {
+    message:
+      'In "lmg" method of (foo): arg 1: {"argGuard":88,"klass":"awaitArg"} - Must be: 88',
+  });
 });
diff --git a/packages/patterns/index.js b/packages/patterns/index.js
index 9dd42f741e..b32e6ea809 100644
--- a/packages/patterns/index.js
+++ b/packages/patterns/index.js
@@ -60,17 +60,20 @@ export {
   mustMatch,
   isAwaitArgGuard,
   assertAwaitArgGuard,
-  getAwaitArgGuardPayload,
   isRawGuard,
   assertRawGuard,
   assertMethodGuard,
-  getMethodGuardPayload,
-  getInterfaceMethodKeys,
   assertInterfaceGuard,
-  getInterfaceGuardPayload,
   kindOf,
 } from './src/patterns/patternMatchers.js';
 
+export {
+  getAwaitArgGuardPayload,
+  getMethodGuardPayload,
+  getInterfaceGuardPayload,
+  getInterfaceMethodKeys,
+} from './src/patterns/getGuardPayloads.js';
+
 // eslint-disable-next-line import/export
 export * from './src/types.js';
 
diff --git a/packages/patterns/src/patterns/getGuardPayloads.js b/packages/patterns/src/patterns/getGuardPayloads.js
new file mode 100644
index 0000000000..9b3d681b90
--- /dev/null
+++ b/packages/patterns/src/patterns/getGuardPayloads.js
@@ -0,0 +1,281 @@
+import { objectMap } from '@endo/common/object-map.js';
+import {
+  ArgGuardListShape,
+  AwaitArgGuardShape,
+  InterfaceGuardPayloadShape,
+  InterfaceGuardShape,
+  M,
+  MethodGuardPayloadShape,
+  MethodGuardShape,
+  RawGuardShape,
+  SyncValueGuardListShape,
+  SyncValueGuardShape,
+  assertAwaitArgGuard,
+  matches,
+  mustMatch,
+} from './patternMatchers.js';
+import { getCopyMapKeys, makeCopyMap } from '../keys/checkKey.js';
+
+// The get*GuardPayload functions exist to adapt to the worlds both
+// before and after https://github.com/endojs/endo/pull/1712 . When
+// given something that would be the expected guard in either world,
+// it returns a *GuardPayload that is valid in the current world. Thus
+// it helps new consumers of these guards cope with old code that
+// would construct and send these guards.
+
+// Because the main use case for this legacy adaptation is in @endo/exo
+// or packages that depend on it, the tests for this legacy adaptation
+// are found in the @endo/exo `test-legacy-guard-tolerance.js`.
+
+// Unlike LegacyAwaitArgGuardShape, LegacyMethodGuardShape,
+// and LegacyInterfaceGuardShape, there is no need for a
+// LegacyRawGuardShape, because raw guards were introduced at
+// https://github.com/endojs/endo/pull/1831 , which was merged well after
+// https://github.com/endojs/endo/pull/1712 . Thus, there was never a
+// `klass:` form of the raw guard.
+
+// TODO At such a time that we decide we no longer need to support code
+// preceding https://github.com/endojs/endo/pull/1712 or guard data
+// generated by that code, all the adaptation complexity in this file
+// should be deleted.
+
+// TODO manually maintain correspondence with AwaitArgGuardPayloadShape
+// because this one needs to be stable and accommodate nested legacy,
+// when that's an issue.
+const LegacyAwaitArgGuardShape = harden({
+  klass: 'awaitArg',
+  argGuard: M.pattern(),
+});
+
+/**
+ * By using this abstraction rather than accessing the properties directly,
+ * we smooth the transition to https://github.com/endojs/endo/pull/1712,
+ * tolerating both the legacy and current guard shapes.
+ *
+ * Note that technically, tolerating the old LegacyAwaitArgGuardShape
+ * is an exploitable bug, in that a record that matches this
+ * shape is also a valid parameter pattern that should allow
+ * an argument that matches that pattern, i.e., a copyRecord argument that
+ * at least contains a `klass: 'awaitArgGuard'` property.
+ *
+ * @param {import('./types.js').AwaitArgGuard} awaitArgGuard
+ * @returns {import('./types.js').AwaitArgGuardPayload}
+ */
+export const getAwaitArgGuardPayload = awaitArgGuard => {
+  if (matches(awaitArgGuard, LegacyAwaitArgGuardShape)) {
+    // @ts-expect-error Legacy adaptor can be ill typed
+    const { klass: _, ...payload } = awaitArgGuard;
+    // @ts-expect-error Legacy adaptor can be ill typed
+    return payload;
+  }
+  assertAwaitArgGuard(awaitArgGuard);
+  return awaitArgGuard.payload;
+};
+harden(getAwaitArgGuardPayload);
+
+// TODO manually maintain correspondence with SyncMethodGuardPayloadShape
+// because this one needs to be stable and accommodate nested legacy,
+// when that's an issue.
+const LegacySyncMethodGuardShape = M.splitRecord(
+  {
+    klass: 'methodGuard',
+    callKind: 'sync',
+    argGuards: SyncValueGuardListShape,
+    returnGuard: SyncValueGuardShape,
+  },
+  {
+    optionalArgGuards: SyncValueGuardListShape,
+    restArgGuard: SyncValueGuardShape,
+  },
+);
+
+// TODO manually maintain correspondence with ArgGuardShape
+// because this one needs to be stable and accommodate nested legacy,
+// when that's an issue.
+const LegacyArgGuardShape = M.or(
+  RawGuardShape,
+  AwaitArgGuardShape,
+  LegacyAwaitArgGuardShape,
+  M.pattern(),
+);
+// TODO manually maintain correspondence with ArgGuardListShape
+// because this one needs to be stable and accommodate nested legacy,
+// when that's an issue.
+const LegacyArgGuardListShape = M.arrayOf(LegacyArgGuardShape);
+
+// TODO manually maintain correspondence with AsyncMethodGuardPayloadShape
+// because this one needs to be stable and accommodate nested legacy,
+// when that's an issue.
+const LegacyAsyncMethodGuardShape = M.splitRecord(
+  {
+    klass: 'methodGuard',
+    callKind: 'async',
+    argGuards: LegacyArgGuardListShape,
+    returnGuard: SyncValueGuardShape,
+  },
+  {
+    optionalArgGuards: ArgGuardListShape,
+    restArgGuard: SyncValueGuardShape,
+  },
+);
+
+// TODO manually maintain correspondence with MethodGuardPayloadShape
+// because this one needs to be stable and accommodate nested legacy,
+// when that's an issue.
+const LegacyMethodGuardShape = M.or(
+  LegacySyncMethodGuardShape,
+  LegacyAsyncMethodGuardShape,
+);
+
+const adaptLegacyArgGuard = argGuard =>
+  matches(argGuard, LegacyAwaitArgGuardShape)
+    ? M.await(getAwaitArgGuardPayload(argGuard).argGuard)
+    : argGuard;
+
+/**
+ * By using this abstraction rather than accessing the properties directly,
+ * we smooth the transition to https://github.com/endojs/endo/pull/1712,
+ * tolerating both the legacy and current guard shapes.
+ *
+ * Unlike LegacyAwaitArgGuardShape, tolerating LegacyMethodGuardShape
+ * does not seem like a currently exploitable bug, because there is not
+ * currently any context where either a methodGuard or a copyRecord would
+ * both be meaningful.
+ *
+ * @param {import('./types.js').MethodGuard} methodGuard
+ * @returns {import('./types.js').MethodGuardPayload}
+ */
+export const getMethodGuardPayload = methodGuard => {
+  if (matches(methodGuard, MethodGuardShape)) {
+    return methodGuard.payload;
+  }
+  mustMatch(methodGuard, LegacyMethodGuardShape, 'legacyMethodGuard');
+  const {
+    // @ts-expect-error Legacy adaptor can be ill typed
+    klass: _,
+    // @ts-expect-error Legacy adaptor can be ill typed
+    callKind,
+    // @ts-expect-error Legacy adaptor can be ill typed
+    returnGuard,
+    // @ts-expect-error Legacy adaptor can be ill typed
+    restArgGuard,
+  } = methodGuard;
+  let {
+    // @ts-expect-error Legacy adaptor can be ill typed
+    argGuards,
+    // @ts-expect-error Legacy adaptor can be ill typed
+    optionalArgGuards,
+  } = methodGuard;
+  if (callKind === 'async') {
+    argGuards = argGuards.map(adaptLegacyArgGuard);
+    optionalArgGuards =
+      optionalArgGuards && optionalArgGuards.map(adaptLegacyArgGuard);
+  }
+  const payload = harden({
+    callKind,
+    argGuards,
+    optionalArgGuards,
+    restArgGuard,
+    returnGuard,
+  });
+  // ensure the adaptation succeeded.
+  mustMatch(payload, MethodGuardPayloadShape, 'internalMethodGuardAdaptor');
+  return payload;
+};
+harden(getMethodGuardPayload);
+
+// TODO manually maintain correspondence with InterfaceGuardPayloadShape
+// because this one needs to be stable and accommodate nested legacy,
+// when that's an issue.
+const LegacyInterfaceGuardShape = M.splitRecord(
+  {
+    klass: 'Interface',
+    interfaceName: M.string(),
+    methodGuards: M.recordOf(
+      M.string(),
+      M.or(MethodGuardShape, LegacyMethodGuardShape),
+    ),
+  },
+  {
+    defaultGuards: M.or(M.undefined(), 'passable', 'raw'),
+    sloppy: M.boolean(),
+    // There is no need to accommodate LegacyMethodGuardShape in
+    // this position, since `symbolMethodGuards happened
+    // after https://github.com/endojs/endo/pull/1712
+    symbolMethodGuards: M.mapOf(M.symbol(), MethodGuardShape),
+  },
+);
+
+const adaptMethodGuard = methodGuard => {
+  if (matches(methodGuard, LegacyMethodGuardShape)) {
+    const {
+      callKind,
+      argGuards,
+      optionalArgGuards = [],
+      restArgGuard = M.any(),
+      returnGuard,
+    } = getMethodGuardPayload(methodGuard);
+    const mCall = callKind === 'sync' ? M.call : M.callWhen;
+    return mCall(...argGuards)
+      .optional(...optionalArgGuards)
+      .rest(restArgGuard)
+      .returns(returnGuard);
+  }
+  return methodGuard;
+};
+
+/**
+ * By using this abstraction rather than accessing the properties directly,
+ * we smooth the transition to https://github.com/endojs/endo/pull/1712,
+ * tolerating both the legacy and current guard shapes.
+ *
+ * Unlike LegacyAwaitArgGuardShape, tolerating LegacyInterfaceGuardShape
+ * does not seem like a currently exploitable bug, because there is not
+ * currently any context where either an interfaceGuard or a copyRecord would
+ * both be meaningful.
+ *
+ * @template {Record<PropertyKey, import('./types.js').MethodGuard>} [T=Record<PropertyKey, import('./types.js').MethodGuard>]
+ * @param {import('./types.js').InterfaceGuard<T>} interfaceGuard
+ * @returns {import('./types.js').InterfaceGuardPayload<T>}
+ */
+export const getInterfaceGuardPayload = interfaceGuard => {
+  if (matches(interfaceGuard, InterfaceGuardShape)) {
+    return interfaceGuard.payload;
+  }
+  mustMatch(interfaceGuard, LegacyInterfaceGuardShape, 'legacyInterfaceGuard');
+  // @ts-expect-error Legacy adaptor can be ill typed
+  // eslint-disable-next-line prefer-const
+  let { klass: _, interfaceName, methodGuards, ...rest } = interfaceGuard;
+  methodGuards = objectMap(methodGuards, adaptMethodGuard);
+  const payload = harden({
+    interfaceName,
+    methodGuards,
+    ...rest,
+  });
+  mustMatch(
+    payload,
+    InterfaceGuardPayloadShape,
+    'internalInterfaceGuardAdaptor',
+  );
+  return payload;
+};
+harden(getInterfaceGuardPayload);
+
+const emptyCopyMap = makeCopyMap([]);
+
+/**
+ * @param {import('./types.js').InterfaceGuard} interfaceGuard
+ * @returns {(string | symbol)[]}
+ */
+export const getInterfaceMethodKeys = interfaceGuard => {
+  const { methodGuards, symbolMethodGuards = emptyCopyMap } =
+    getInterfaceGuardPayload(interfaceGuard);
+  /** @type {(string | symbol)[]} */
+  // TODO at-ts-expect-error works locally but not from @endo/exo
+  // @ts-ignore inference is too weak to see this is ok
+  return harden([
+    ...Reflect.ownKeys(methodGuards),
+    ...getCopyMapKeys(symbolMethodGuards),
+  ]);
+};
+harden(getInterfaceMethodKeys);
diff --git a/packages/patterns/src/patterns/patternMatchers.js b/packages/patterns/src/patterns/patternMatchers.js
index aafeb33413..dae54dc48d 100644
--- a/packages/patterns/src/patterns/patternMatchers.js
+++ b/packages/patterns/src/patterns/patternMatchers.js
@@ -31,7 +31,6 @@ import {
   checkCopyBag,
   getCopyMapEntryArray,
   makeCopyMap,
-  getCopyMapKeys,
 } from '../keys/checkKey.js';
 import { generateCollectionPairEntries } from '../keys/keycollection-operators.js';
 
@@ -1738,7 +1737,7 @@ const AwaitArgGuardPayloadShape = harden({
   argGuard: M.pattern(),
 });
 
-const AwaitArgGuardShape = M.kind('guard:awaitArgGuard');
+export const AwaitArgGuardShape = M.kind('guard:awaitArgGuard');
 
 /**
  * @param {any} specimen
@@ -1757,19 +1756,6 @@ export const assertAwaitArgGuard = specimen => {
 };
 harden(assertAwaitArgGuard);
 
-/**
- * By using this abstraction rather than accessing the properties directly,
- * we smooth the transition to https://github.com/endojs/endo/pull/1712
- *
- * @param {import('./types.js').AwaitArgGuard} awaitArgGuard
- * @returns {import('./types.js').AwaitArgGuardPayload}
- */
-export const getAwaitArgGuardPayload = awaitArgGuard => {
-  assertAwaitArgGuard(awaitArgGuard);
-  return awaitArgGuard.payload;
-};
-harden(getAwaitArgGuardPayload);
-
 /**
  * @param {import('./types.js').Pattern} argPattern
  * @returns {import('./types.js').AwaitArgGuard}
@@ -1787,7 +1773,7 @@ const makeAwaitArgGuard = argPattern => {
 
 const RawGuardPayloadShape = M.record();
 
-const RawGuardShape = M.kind('guard:rawGuard');
+export const RawGuardShape = M.kind('guard:rawGuard');
 
 export const isRawGuard = specimen => matches(specimen, RawGuardShape);
 
@@ -1802,12 +1788,12 @@ const makeRawGuard = () => makeTagged('guard:rawGuard', {});
 // M.call(...)
 // M.callWhen(...)
 
-const SyncValueGuardShape = M.or(RawGuardShape, M.pattern());
+export const SyncValueGuardShape = M.or(RawGuardShape, M.pattern());
 
-const SyncValueGuardListShape = M.arrayOf(SyncValueGuardShape);
+export const SyncValueGuardListShape = M.arrayOf(SyncValueGuardShape);
 
 const ArgGuardShape = M.or(RawGuardShape, AwaitArgGuardShape, M.pattern());
-const ArgGuardListShape = M.arrayOf(ArgGuardShape);
+export const ArgGuardListShape = M.arrayOf(ArgGuardShape);
 
 const SyncMethodGuardPayloadShape = harden({
   callKind: 'sync',
@@ -1825,12 +1811,12 @@ const AsyncMethodGuardPayloadShape = harden({
   returnGuard: SyncValueGuardShape,
 });
 
-const MethodGuardPayloadShape = M.or(
+export const MethodGuardPayloadShape = M.or(
   SyncMethodGuardPayloadShape,
   AsyncMethodGuardPayloadShape,
 );
 
-const MethodGuardShape = M.kind('guard:methodGuard');
+export const MethodGuardShape = M.kind('guard:methodGuard');
 
 /**
  * @param {any} specimen
@@ -1841,19 +1827,6 @@ export const assertMethodGuard = specimen => {
 };
 harden(assertMethodGuard);
 
-/**
- * By using this abstraction rather than accessing the properties directly,
- * we smooth the transition to https://github.com/endojs/endo/pull/1712
- *
- * @param {import('./types.js').MethodGuard} methodGuard
- * @returns {import('./types.js').MethodGuardPayload}
- */
-export const getMethodGuardPayload = methodGuard => {
-  assertMethodGuard(methodGuard);
-  return methodGuard.payload;
-};
-harden(getMethodGuardPayload);
-
 /**
  * @param {'sync'|'async'} callKind
  * @param {import('./types.js').ArgGuard[]} argGuards
@@ -1898,7 +1871,7 @@ const makeMethodGuardMaker = (
     },
   });
 
-const InterfaceGuardPayloadShape = M.splitRecord(
+export const InterfaceGuardPayloadShape = M.splitRecord(
   {
     interfaceName: M.string(),
     methodGuards: M.recordOf(M.string(), MethodGuardShape),
@@ -1910,7 +1883,7 @@ const InterfaceGuardPayloadShape = M.splitRecord(
   },
 );
 
-const InterfaceGuardShape = M.kind('guard:interfaceGuard');
+export const InterfaceGuardShape = M.kind('guard:interfaceGuard');
 
 /**
  * @param {any} specimen
@@ -1921,39 +1894,6 @@ export const assertInterfaceGuard = specimen => {
 };
 harden(assertInterfaceGuard);
 
-/**
- * By using this abstraction rather than accessing the properties directly,
- * we smooth the transition to https://github.com/endojs/endo/pull/1712
- *
- * @template {Record<PropertyKey, import('./types.js').MethodGuard>} [T=Record<PropertyKey, import('./types.js').MethodGuard>]
- * @param {import('./types.js').InterfaceGuard<T>} interfaceGuard
- * @returns {import('./types.js').InterfaceGuardPayload<T>}
- */
-export const getInterfaceGuardPayload = interfaceGuard => {
-  assertInterfaceGuard(interfaceGuard);
-  return interfaceGuard.payload;
-};
-harden(getInterfaceGuardPayload);
-
-const emptyCopyMap = makeCopyMap([]);
-
-/**
- * @param {import('./types.js').InterfaceGuard} interfaceGuard
- * @returns {(string | symbol)[]}
- */
-export const getInterfaceMethodKeys = interfaceGuard => {
-  const { methodGuards, symbolMethodGuards = emptyCopyMap } =
-    getInterfaceGuardPayload(interfaceGuard);
-  /** @type {(string | symbol)[]} */
-  // TODO at-ts-expect-error works locally but not from @endo/exo
-  // @ts-ignore inference is too weak to see this is ok
-  return harden([
-    ...Reflect.ownKeys(methodGuards),
-    ...getCopyMapKeys(symbolMethodGuards),
-  ]);
-};
-harden(getInterfaceMethodKeys);
-
 /**
  * @template {Record<PropertyKey, import('./types.js').MethodGuard>} [M = Record<PropertyKey, import('./types.js').MethodGuard>]
  * @param {string} interfaceName