diff --git a/docs/public/editor/autocomplete-data.json b/docs/public/editor/autocomplete-data.json
index e1cd15cba2c..b24a883f0d1 100644
--- a/docs/public/editor/autocomplete-data.json
+++ b/docs/public/editor/autocomplete-data.json
@@ -546,12 +546,6 @@
         }
       }
     },
-    "disable-model-invocation": {
-      "type": "boolean",
-      "desc": "Controls whether the custom agent should disable model invocation.",
-      "enum": [true, false],
-      "leaf": true
-    },
     "secrets": {
       "type": "object",
       "desc": "Secret values passed to workflow execution."
@@ -1364,7 +1358,7 @@
             },
             "mode": {
               "type": "string",
-              "desc": "Integration mode: 'cli' (recommended) installs @playwright/cli via npm for token-efficient CLI invocations — use play...",
+              "desc": "Integration mode: 'cli' (recommended) installs @playwright/cli via npm for token-efficient CLI invocations \u2014 use play...",
               "enum": ["cli", "mcp"],
               "leaf": true
             }
@@ -2648,7 +2642,6 @@
     "steps",
     "post-steps",
     "features",
-    "disable-model-invocation",
     "secrets",
     "secret-masking",
     "bots",
diff --git a/docs/scripts/generate-autocomplete-data.js b/docs/scripts/generate-autocomplete-data.js
index c8c20e93184..99ad44944a1 100644
--- a/docs/scripts/generate-autocomplete-data.js
+++ b/docs/scripts/generate-autocomplete-data.js
@@ -36,7 +36,7 @@ const ROOT_SORT_ORDER = [
   'labels', 'metadata', 'tracker-id', 'source', 'run-name', 'runs-on',
   'timeout-minutes', 'concurrency', 'environment', 'container', 'services',
   'network', 'sandbox', 'plugins', 'if', 'steps', 'post-steps',
-  'features', 'disable-model-invocation', 'secrets',
+  'features', 'secrets',
   'secret-masking', 'bots', 'user-rate-limit', 'strict', 'safe-inputs',
   'runtimes', 'jobs',
 ];
diff --git a/pkg/constants/README.md b/pkg/constants/README.md
index ad25289adc4..36f46b5eb70 100644
--- a/pkg/constants/README.md
+++ b/pkg/constants/README.md
@@ -405,7 +405,7 @@ constants.PriorityJobFields       // []string{"name","runs-on","needs","if","per
 constants.PriorityWorkflowFields  // []string{"on","permissions","if","network","imports",...}
 
 // Fields silently ignored during frontmatter validation
-constants.IgnoredFrontmatterFields // []string{"user-invokable"}
+constants.IgnoredFrontmatterFields // []string{}
 
 // Fields forbidden in shared/imported workflows (only valid in main workflows)
 constants.SharedWorkflowForbiddenFields // []string{"on","concurrency","container",...}
diff --git a/pkg/constants/constants.go b/pkg/constants/constants.go
index ee77ecb9ccd..d62e3b2fb68 100644
--- a/pkg/constants/constants.go
+++ b/pkg/constants/constants.go
@@ -314,8 +314,7 @@ var PriorityJobFields = []string{"name", "runs-on", "needs", "if", "permissions"
 var PriorityWorkflowFields = []string{"on", "permissions", "if", "network", "imports", "safe-outputs", "steps"}
 
 // IgnoredFrontmatterFields are fields that should be silently ignored during frontmatter validation
-// NOTE: user-invokable is a GitHub Copilot custom agent field that is not part of the gh-aw schema
-var IgnoredFrontmatterFields = []string{"user-invokable"}
+var IgnoredFrontmatterFields = []string{}
 
 // SharedWorkflowForbiddenFields lists fields that cannot be used in shared/included workflows.
 // These fields are only allowed in main workflows (workflows with an 'on' trigger field).
diff --git a/pkg/parser/schema_location_test.go b/pkg/parser/schema_location_test.go
index 6a3076fd374..64e67559eec 100644
--- a/pkg/parser/schema_location_test.go
+++ b/pkg/parser/schema_location_test.go
@@ -530,3 +530,27 @@ func TestValidateMainWorkflowFrontmatterWithSchemaAndLocation_RejectsTopLevelCom
 		t.Fatalf("expected unknown property error for command, got: %v", err)
 	}
 }
+
+func TestValidateIncludedFileFrontmatterWithSchemaAndLocation_SkipsCustomAgentFiles(t *testing.T) {
+	// Custom agent files may contain Copilot-specific fields that are not in the
+	// gh-aw main workflow schema (e.g. user-invokable, disable-model-invocation,
+	// tools as an array).  Schema validation must be skipped for these files.
+	agentFrontmatter := map[string]any{
+		"description":              "My custom agent",
+		"user-invokable":           true,
+		"disable-model-invocation": false,
+	}
+
+	agentPaths := []string{
+		"/repo/.github/agents/my-agent.md",
+		".github/agents/my-agent.md",
+		"/some/path/.github/agents/sub/helper.md",
+	}
+
+	for _, path := range agentPaths {
+		err := ValidateIncludedFileFrontmatterWithSchemaAndLocation(agentFrontmatter, path)
+		if err != nil {
+			t.Errorf("expected custom agent file %q to pass validation without errors, got: %v", path, err)
+		}
+	}
+}
diff --git a/pkg/parser/schema_utilities_test.go b/pkg/parser/schema_utilities_test.go
index 4f06fd4ee75..55d2e9f36a2 100644
--- a/pkg/parser/schema_utilities_test.go
+++ b/pkg/parser/schema_utilities_test.go
@@ -46,18 +46,6 @@ func TestFilterIgnoredFields(t *testing.T) {
 				"engine": "claude",
 			},
 		},
-		{
-			name: "frontmatter with user-invokable - should be filtered",
-			frontmatter: map[string]any{
-				"user-invokable": true,
-				"on":             "push",
-				"engine":         "claude",
-			},
-			expected: map[string]any{
-				"on":     "push",
-				"engine": "claude",
-			},
-		},
 	}
 
 	for _, tt := range tests {
diff --git a/pkg/parser/schema_validation.go b/pkg/parser/schema_validation.go
index 984a3cd1c45..1d379f2164b 100644
--- a/pkg/parser/schema_validation.go
+++ b/pkg/parser/schema_validation.go
@@ -130,6 +130,14 @@ func ValidateMainWorkflowFrontmatterWithSchemaAndLocation(frontmatter map[string
 // ValidateIncludedFileFrontmatterWithSchemaAndLocation validates included file frontmatter with file location info
 func ValidateIncludedFileFrontmatterWithSchemaAndLocation(frontmatter map[string]any, filePath string) error {
 	schemaValidationLog.Printf("Validating included file frontmatter: file=%s, fields=%d", filePath, len(frontmatter))
+
+	// Custom agent files (.github/agents/*.md) follow the Copilot agent format,
+	// which differs from the gh-aw workflow schema. Skip schema validation for them.
+	if isCustomAgentFile(filePath) {
+		schemaValidationLog.Printf("Skipping schema validation for custom agent file: %s", filePath)
+		return nil
+	}
+
 	// Filter out ignored fields before validation
 	filtered := filterIgnoredFields(frontmatter)