diff --git a/lib/param_parsing/environment.go b/lib/param_parsing/environment.go
index ff4c36b4..1d94e7e7 100644
--- a/lib/param_parsing/environment.go
+++ b/lib/param_parsing/environment.go
@@ -5,12 +5,15 @@ import "os"
 func GetParamsFromEnvironment(params Params) Params {
 	if envVersion := os.Getenv("TF_VERSION"); envVersion != "" {
 		params.Version = envVersion
+		logger.Debugf("Using version from environment variable \"TF_VERSION\": %q", envVersion)
 	}
 	if envDefaultVersion := os.Getenv("TF_DEFAULT_VERSION"); envDefaultVersion != "" {
 		params.DefaultVersion = envDefaultVersion
+		logger.Debugf("Using default-version from environment variable \"TF_DEFAULT_VERSION\": %q", envDefaultVersion)
 	}
 	if envProduct := os.Getenv("TF_PRODUCT"); envProduct != "" {
 		params.Product = envProduct
+		logger.Debugf("Using product from environment variable \"TF_PRODUCT\": %q", envProduct)
 	}
 	return params
 }
diff --git a/lib/param_parsing/environment_test.go b/lib/param_parsing/environment_test.go
index d1f3da01..f4574100 100644
--- a/lib/param_parsing/environment_test.go
+++ b/lib/param_parsing/environment_test.go
@@ -3,9 +3,12 @@ package param_parsing
 import (
 	"os"
 	"testing"
+
+	"github.com/warrensbox/terraform-switcher/lib"
 )
 
 func TestGetParamsFromEnvironment_version_from_env(t *testing.T) {
+	logger = lib.InitLogger("DEBUG")
 	var params Params
 	expected := "1.0.0_from_env"
 	_ = os.Setenv("TF_VERSION", expected)
@@ -30,6 +33,7 @@ func TestGetParamsFromEnvironment_default_version_from_env(t *testing.T) {
 }
 
 func TestGetParamsFromEnvironment_product_from_env(t *testing.T) {
+	logger = lib.InitLogger("DEBUG")
 	var params Params
 	expected := "opentofu"
 	_ = os.Setenv("TF_PRODUCT", expected)
diff --git a/lib/param_parsing/parameters_test.go b/lib/param_parsing/parameters_test.go
index d2d510a2..69e13236 100644
--- a/lib/param_parsing/parameters_test.go
+++ b/lib/param_parsing/parameters_test.go
@@ -169,6 +169,7 @@ func checkExpectedPrecedenceVersion(t *testing.T, expectedVersion string, expect
 }
 
 func TestGetParameters_check_config_precedence(t *testing.T) {
+	logger = lib.InitLogger("DEBUG")
 	t.Cleanup(func() {
 		getopt.CommandLine = getopt.New()
 	})
diff --git a/lib/param_parsing/terraform_version.go b/lib/param_parsing/terraform_version.go
index eed498ef..e9b08ad4 100644
--- a/lib/param_parsing/terraform_version.go
+++ b/lib/param_parsing/terraform_version.go
@@ -1,10 +1,11 @@
 package param_parsing
 
 import (
-	"github.com/warrensbox/terraform-switcher/lib"
 	"os"
 	"path/filepath"
 	"strings"
+
+	"github.com/warrensbox/terraform-switcher/lib"
 )
 
 const terraformVersionFileName = ".terraform-version"
@@ -19,6 +20,7 @@ func GetParamsFromTerraformVersion(params Params) (Params, error) {
 			return params, err
 		}
 		params.Version = strings.TrimSpace(string(content))
+		logger.Debugf("Using version from %q: %q", filePath, params.Version)
 	}
 	return params, nil
 }
diff --git a/lib/param_parsing/terragrunt.go b/lib/param_parsing/terragrunt.go
index db6d5806..0e20d796 100644
--- a/lib/param_parsing/terragrunt.go
+++ b/lib/param_parsing/terragrunt.go
@@ -2,10 +2,11 @@ package param_parsing
 
 import (
 	"fmt"
+	"path/filepath"
+
 	"github.com/hashicorp/hcl/v2/gohcl"
 	"github.com/hashicorp/hcl/v2/hclparse"
 	"github.com/warrensbox/terraform-switcher/lib"
-	"path/filepath"
 )
 
 const terraGruntFileName = "terragrunt.hcl"
@@ -34,6 +35,7 @@ func GetVersionFromTerragrunt(params Params) (Params, error) {
 			return params, fmt.Errorf("no version found matching %q", versionFromTerragrunt.TerraformVersionConstraint)
 		}
 		params.Version = version
+		logger.Debugf("Using version from %q: %q", filePath, params.Version)
 	}
 	return params, nil
 }
diff --git a/lib/param_parsing/tfswitch.go b/lib/param_parsing/tfswitch.go
index 89e78a24..1c5d3b38 100644
--- a/lib/param_parsing/tfswitch.go
+++ b/lib/param_parsing/tfswitch.go
@@ -1,10 +1,11 @@
 package param_parsing
 
 import (
-	"github.com/warrensbox/terraform-switcher/lib"
 	"os"
 	"path/filepath"
 	"strings"
+
+	"github.com/warrensbox/terraform-switcher/lib"
 )
 
 const tfSwitchFileName = ".tfswitchrc"
@@ -19,6 +20,7 @@ func GetParamsFromTfSwitch(params Params) (Params, error) {
 			return params, err
 		}
 		params.Version = strings.TrimSpace(string(content))
+		logger.Debugf("Using version from %q: %q", filePath, params.Version)
 	}
 	return params, nil
 }
diff --git a/lib/param_parsing/toml.go b/lib/param_parsing/toml.go
index 1755195d..2ac6ba8c 100644
--- a/lib/param_parsing/toml.go
+++ b/lib/param_parsing/toml.go
@@ -29,18 +29,23 @@ func getParamsTOML(params Params) (Params, error) {
 
 		if viperParser.Get("bin") != nil {
 			params.CustomBinaryPath = os.ExpandEnv(viperParser.GetString("bin"))
+			logger.Debugf("Using \"bin\" from %q: %q", tomlPath, params.CustomBinaryPath)
 		}
 		if viperParser.Get("log-level") != nil {
 			params.LogLevel = viperParser.GetString("log-level")
+			logger.Debugf("Using \"log-level\" from %q: %q", tomlPath, params.LogLevel)
 		}
 		if viperParser.Get("version") != nil {
 			params.Version = viperParser.GetString("version")
+			logger.Debugf("Using \"version\" from %q: %q", tomlPath, params.Version)
 		}
 		if viperParser.Get("default-version") != nil {
 			params.DefaultVersion = viperParser.GetString("default-version")
+			logger.Debugf("Using \"default-version\" from %q: %q", tomlPath, params.DefaultVersion)
 		}
 		if configKey := "product"; viperParser.Get(configKey) != nil {
 			params.Product = viperParser.GetString(configKey)
+			logger.Debugf("Using %q from %q: %q", configKey, tomlPath, params.Product)
 		}
 	}
 	return params, nil
diff --git a/lib/param_parsing/versiontf.go b/lib/param_parsing/versiontf.go
index d95b2f26..f7ae98ec 100644
--- a/lib/param_parsing/versiontf.go
+++ b/lib/param_parsing/versiontf.go
@@ -59,6 +59,7 @@ func GetVersionFromVersionsTF(params Params) (Params, error) {
 		return params, err2
 	}
 	params.Version = version
+	logger.Debugf("Using version from Terraform module at %q: %q", relPath, params.Version)
 	return params, nil
 }
 
@@ -66,6 +67,10 @@ func isTerraformModule(params Params) bool {
 	module, err := tfconfig.LoadModule(params.ChDirPath)
 	if err != nil {
 		logger.Warnf("Error parsing Terraform module: %v", err)
+		return false
+	}
+	if len(module.RequiredCore) == 0 {
+		logger.Debugf("No required version constraints defined by Terraform module at %q", params.ChDirPath)
 	}
 	return err == nil && len(module.RequiredCore) > 0
 }