diff --git a/Controllers/ForAgentsController.php b/Controllers/ForAgentsController.php
index 467c524..5dda808 100644
--- a/Controllers/ForAgentsController.php
+++ b/Controllers/ForAgentsController.php
@@ -18,13 +18,22 @@ class ForAgentsController extends Controller
 {
     public function __invoke(): JsonResponse
     {
-        // Cache for 1 hour since this is static data
-        $data = Cache::remember('agentic.for-agents.json', 3600, function () {
+        $ttl = (int) config('mcp.cache.for_agents_ttl', 3600);
+
+        $data = Cache::remember($this->cacheKey(), $ttl, function () {
             return $this->getAgentData();
         });
 
         return response()->json($data)
-            ->header('Cache-Control', 'public, max-age=3600');
+            ->header('Cache-Control', "public, max-age={$ttl}");
+    }
+
+    /**
+     * Namespaced cache key, configurable to prevent cross-module collisions.
+     */
+    public function cacheKey(): string
+    {
+        return (string) config('mcp.cache.for_agents_key', 'agentic.for-agents.json');
     }
 
     private function getAgentData(): array
diff --git a/TODO.md b/TODO.md
index c69793b..81421a8 100644
--- a/TODO.md
+++ b/TODO.md
@@ -143,10 +143,12 @@ Production-quality task list for the AI agent orchestration package.
   - Updated blade template to use `permissions`, `getMaskedKey()`, `togglePermission()`
   - Added integration tests in `tests/Feature/ApiKeyManagerTest.php`
 
-- [ ] **CQ-003: ForAgentsController cache key not namespaced**
+- [x] **CQ-003: ForAgentsController cache key not namespaced** (FIXED 2026-02-23)
   - Location: `Controllers/ForAgentsController.php`
   - Issue: `Cache::remember('agentic.for-agents.json', ...)` could collide
-  - Fix: Add workspace prefix or use config-based key
+  - Fix: Cache key and TTL now driven by `mcp.cache.for_agents_key` / `mcp.cache.for_agents_ttl` config
+  - Added `cacheKey()` public method and config entries in `config.php`
+  - Tests added in `tests/Feature/ForAgentsControllerTest.php`
 
 ### Performance
 
diff --git a/config.php b/config.php
index 491a94a..3146366 100644
--- a/config.php
+++ b/config.php
@@ -56,4 +56,19 @@ return [
         'drafts_path' => 'app/Mod/Agentic/Resources/drafts',
     ],
 
+    /*
+    |--------------------------------------------------------------------------
+    | Cache Keys
+    |--------------------------------------------------------------------------
+    |
+    | Namespaced cache keys used by agentic endpoints. Override these in your
+    | application config to prevent collisions with other modules.
+    |
+    */
+
+    'cache' => [
+        'for_agents_key' => 'agentic.for-agents.json',
+        'for_agents_ttl' => 3600,
+    ],
+
 ];
diff --git a/tests/Feature/ForAgentsControllerTest.php b/tests/Feature/ForAgentsControllerTest.php
new file mode 100644
index 0000000..99589e3
--- /dev/null
+++ b/tests/Feature/ForAgentsControllerTest.php
@@ -0,0 +1,148 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * Tests for ForAgentsController cache key namespacing (CQ-003).
+ *
+ * Verifies that the cache key is config-based to prevent cross-module collisions,
+ * and that cache invalidation uses the same namespaced key.
+ */
+
+use Core\Mod\Agentic\Controllers\ForAgentsController;
+use Illuminate\Support\Facades\Cache;
+
+// =========================================================================
+// Cache Key Tests
+// =========================================================================
+
+describe('ForAgentsController cache key', function () {
+    it('uses the default namespaced cache key', function () {
+        $controller = new ForAgentsController();
+
+        expect($controller->cacheKey())->toBe('agentic.for-agents.json');
+    });
+
+    it('uses a custom cache key when configured', function () {
+        config(['mcp.cache.for_agents_key' => 'custom-module.for-agents.json']);
+
+        $controller = new ForAgentsController();
+
+        expect($controller->cacheKey())->toBe('custom-module.for-agents.json');
+    });
+
+    it('returns to default key after config is cleared', function () {
+        config(['mcp.cache.for_agents_key' => null]);
+
+        $controller = new ForAgentsController();
+
+        expect($controller->cacheKey())->toBe('agentic.for-agents.json');
+    });
+});
+
+// =========================================================================
+// Cache Behaviour Tests
+// =========================================================================
+
+describe('ForAgentsController cache behaviour', function () {
+    it('stores data under the namespaced cache key', function () {
+        Cache::fake();
+
+        $controller = new ForAgentsController();
+        $controller();
+
+        $key = $controller->cacheKey();
+        expect(Cache::has($key))->toBeTrue();
+    });
+
+    it('returns cached data on subsequent calls', function () {
+        Cache::fake();
+
+        $controller = new ForAgentsController();
+        $first = $controller();
+        $second = $controller();
+
+        expect($first->getContent())->toBe($second->getContent());
+    });
+
+    it('respects the configured TTL', function () {
+        config(['mcp.cache.for_agents_ttl' => 7200]);
+        Cache::fake();
+
+        $controller = new ForAgentsController();
+        $response = $controller();
+
+        expect($response->headers->get('Cache-Control'))->toContain('max-age=7200');
+    });
+
+    it('uses default TTL of 3600 when not configured', function () {
+        config(['mcp.cache.for_agents_ttl' => null]);
+        Cache::fake();
+
+        $controller = new ForAgentsController();
+        $response = $controller();
+
+        expect($response->headers->get('Cache-Control'))->toContain('max-age=3600');
+    });
+
+    it('can be invalidated using the namespaced key', function () {
+        Cache::fake();
+
+        $controller = new ForAgentsController();
+        $controller();
+
+        $key = $controller->cacheKey();
+        expect(Cache::has($key))->toBeTrue();
+
+        Cache::forget($key);
+        expect(Cache::has($key))->toBeFalse();
+    });
+
+    it('stores data under the custom key when configured', function () {
+        config(['mcp.cache.for_agents_key' => 'tenant-a.for-agents.json']);
+        Cache::fake();
+
+        $controller = new ForAgentsController();
+        $controller();
+
+        expect(Cache::has('tenant-a.for-agents.json'))->toBeTrue();
+        expect(Cache::has('agentic.for-agents.json'))->toBeFalse();
+    });
+});
+
+// =========================================================================
+// Response Structure Tests
+// =========================================================================
+
+describe('ForAgentsController response', function () {
+    it('returns a JSON response', function () {
+        Cache::fake();
+
+        $controller = new ForAgentsController();
+        $response = $controller();
+
+        expect($response->headers->get('Content-Type'))->toContain('application/json');
+    });
+
+    it('response contains platform information', function () {
+        Cache::fake();
+
+        $controller = new ForAgentsController();
+        $response = $controller();
+        $data = json_decode($response->getContent(), true);
+
+        expect($data)->toHaveKey('platform')
+            ->and($data['platform'])->toHaveKey('name');
+    });
+
+    it('response contains capabilities', function () {
+        Cache::fake();
+
+        $controller = new ForAgentsController();
+        $response = $controller();
+        $data = json_decode($response->getContent(), true);
+
+        expect($data)->toHaveKey('capabilities')
+            ->and($data['capabilities'])->toHaveKey('mcp_servers');
+    });
+});