From 7c4f378313daeb637ea469beaa140bd8a22916cf Mon Sep 17 00:00:00 2001
From: Pavel Jbanov <pavelgj@gmail.com>
Date: Wed, 19 Nov 2025 11:12:05 -0500
Subject: [PATCH 1/2] fix(js/ai): fixed dynamic tools becoming non-dynamic once
 registered

test case in question

```ts
  it('should remain dynamic after registration', () => {
    const dynamic = tool({ name: 'dynamic', description: 'test' });
    assert.strictEqual(isDynamicTool(dynamic), true);

    registry.registerAction('tool', dynamic);

    assert.strictEqual(isDynamicTool(dynamic), true);
  });
  ```
---
 js/ai/src/tool.ts        |  2 +-
 js/ai/tests/tool_test.ts | 55 ++++++++++++++++++++++++++++++++++++++--
 2 files changed, 54 insertions(+), 3 deletions(-)

diff --git a/js/ai/src/tool.ts b/js/ai/src/tool.ts
index 19c9665676..0f8327bf96 100644
--- a/js/ai/src/tool.ts
+++ b/js/ai/src/tool.ts
@@ -384,7 +384,7 @@ export function isToolResponse(part: Part): part is ToolResponsePart {
 }
 
 export function isDynamicTool(t: unknown): t is ToolAction {
-  return isAction(t) && !t.__registry;
+  return isAction(t) && t.__action?.metadata?.dynamic === true;
 }
 
 export function interrupt<I extends z.ZodTypeAny, O extends z.ZodTypeAny>(
diff --git a/js/ai/tests/tool_test.ts b/js/ai/tests/tool_test.ts
index 74a0194e91..e4fc6c6d12 100644
--- a/js/ai/tests/tool_test.ts
+++ b/js/ai/tests/tool_test.ts
@@ -14,12 +14,17 @@
  * limitations under the License.
  */
 
-import { z } from '@genkit-ai/core';
+import { action, z } from '@genkit-ai/core';
 import { initNodeFeatures } from '@genkit-ai/core/node';
 import { Registry } from '@genkit-ai/core/registry';
 import * as assert from 'assert';
 import { afterEach, describe, it } from 'node:test';
-import { defineInterrupt, defineTool } from '../src/tool.js';
+import {
+  defineInterrupt,
+  defineTool,
+  isDynamicTool,
+  tool,
+} from '../src/tool.js';
 
 initNodeFeatures();
 
@@ -109,6 +114,52 @@ describe('defineInterrupt', () => {
   });
 });
 
+describe('isDynamicTool', () => {
+  let registry = new Registry();
+  registry.apiStability = 'beta';
+  afterEach(() => {
+    registry = new Registry();
+    registry.apiStability = 'beta';
+  });
+
+  it('should return true for a dynamic tool', () => {
+    const dynamic = tool({ name: 'dynamic', description: 'test' });
+    assert.strictEqual(isDynamicTool(dynamic), true);
+  });
+
+  it('should remain dynamic after registration', () => {
+    const dynamic = tool({ name: 'dynamic', description: 'test' });
+    assert.strictEqual(isDynamicTool(dynamic), true);
+
+    registry.registerAction('tool', dynamic);
+
+    assert.strictEqual(isDynamicTool(dynamic), true);
+  });
+
+  it('should return false for a registered tool', () => {
+    const regular = defineTool(
+      registry,
+      { name: 'regular', description: 'test' },
+      async () => {}
+    );
+    assert.strictEqual(isDynamicTool(regular), false);
+  });
+
+  it('should return false for a non-tool action', () => {
+    const regularAction = action(
+      { actionType: 'util', name: 'regularAction', description: 'test' },
+      async () => {}
+    );
+    assert.strictEqual(isDynamicTool(regularAction), false);
+  });
+
+  it('should return false for a non-action', () => {
+    assert.strictEqual(isDynamicTool({}), false);
+    assert.strictEqual(isDynamicTool('tool'), false);
+    assert.strictEqual(isDynamicTool(123), false);
+  });
+});
+
 describe('defineTool', () => {
   let registry = new Registry();
   registry.apiStability = 'beta';

From 04f02fb758a54c527ada6a65c353e90d708f4080 Mon Sep 17 00:00:00 2001
From: Pavel Jbanov <pavelgj@gmail.com>
Date: Wed, 19 Nov 2025 11:23:01 -0500
Subject: [PATCH 2/2] same for resources

---
 js/ai/src/resource.ts                 |  3 ++-
 js/ai/tests/resource/resource_test.ts | 16 ++++++++++++++--
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/js/ai/src/resource.ts b/js/ai/src/resource.ts
index 1ffb8192d1..a7964b4a87 100644
--- a/js/ai/src/resource.ts
+++ b/js/ai/src/resource.ts
@@ -138,6 +138,7 @@ export function defineResource(
 ): ResourceAction {
   const action = dynamicResource(opts, fn);
   action.matches = createMatcher(opts.uri, opts.template);
+  action.__action.metadata.dynamic = false;
   registry.registerAction('resource', action);
   return action;
 }
@@ -193,7 +194,7 @@ export async function findMatchingResource(
 
 /** Checks whether provided object is a dynamic resource. */
 export function isDynamicResourceAction(t: unknown): t is ResourceAction {
-  return isAction(t) && !t.__registry;
+  return isAction(t) && t.__action?.metadata?.dynamic === true;
 }
 
 /**
diff --git a/js/ai/tests/resource/resource_test.ts b/js/ai/tests/resource/resource_test.ts
index fff8fa88fd..558c6a2ea4 100644
--- a/js/ai/tests/resource/resource_test.ts
+++ b/js/ai/tests/resource/resource_test.ts
@@ -23,6 +23,7 @@ import {
   dynamicResource,
   findMatchingResource,
   isDynamicResourceAction,
+  resource,
 } from '../../src/resource.js';
 import { defineEchoModel } from '../helpers.js';
 
@@ -58,7 +59,7 @@ describe('resource', () => {
         uri: 'foo://bar',
       },
       type: 'resource',
-      dynamic: true,
+      dynamic: false,
     });
 
     assert.strictEqual(testResource.matches({ uri: 'foo://bar' }), true);
@@ -229,7 +230,7 @@ describe('resource', () => {
         uri: undefined,
       },
       type: 'resource',
-      dynamic: true,
+      dynamic: false,
     });
 
     const gotBaz = await findMatchingResource(registry, resList, {
@@ -286,4 +287,15 @@ describe('isDynamicResourceAction', () => {
       true
     );
   });
+
+  it('should remain dynamic after registration', () => {
+    const dynamic = resource({ uri: 'bar://baz' }, () => ({
+      content: [{ text: `bar` }],
+    }));
+    assert.strictEqual(isDynamicResourceAction(dynamic), true);
+
+    registry.registerAction('resource', dynamic);
+
+    assert.strictEqual(isDynamicResourceAction(dynamic), true);
+  });
 });