diff --git a/src/lib/o11y/api-metrics.server.test.ts b/src/lib/o11y/api-metrics.server.test.ts
new file mode 100644
index 000000000..e3cee793b
--- /dev/null
+++ b/src/lib/o11y/api-metrics.server.test.ts
@@ -0,0 +1,46 @@
+import { describe, expect, it } from '@jest/globals';
+import { getToolsAvailable, getToolsUsed } from '@/lib/o11y/api-metrics.server';
+import type { GatewayRequest } from '@/lib/providers/openrouter/types';
+
+describe('api metrics tool extraction', () => {
+  it('returns empty toolsAvailable when chat completions tools is a non-array object', () => {
+    const request = {
+      kind: 'chat_completions',
+      body: {
+        model: 'x-ai/grok-4.1-fast',
+        messages: [{ role: 'user', content: 'Hello' }],
+        tools: { todowrite: false, task: false },
+      },
+    } as unknown as GatewayRequest;
+
+    expect(getToolsAvailable(request)).toEqual([]);
+  });
+
+  it('extracts chat completions tools when tools is an array', () => {
+    const request = {
+      kind: 'chat_completions',
+      body: {
+        model: 'x-ai/grok-4.1-fast',
+        messages: [{ role: 'user', content: 'Hello' }],
+        tools: [
+          { type: 'function', function: { name: 'read_file', arguments: '{}' } },
+          { type: 'custom', custom: { name: 'run_sql' } },
+        ],
+      },
+    } as unknown as GatewayRequest;
+
+    expect(getToolsAvailable(request)).toEqual(['function:read_file', 'custom:run_sql']);
+  });
+
+  it('returns empty toolsUsed when chat completions has no assistant tool calls', () => {
+    const request = {
+      kind: 'chat_completions',
+      body: {
+        model: 'x-ai/grok-4.1-fast',
+        messages: [{ role: 'user', content: 'Hello' }],
+      },
+    } as unknown as GatewayRequest;
+
+    expect(getToolsUsed(request)).toEqual([]);
+  });
+});
diff --git a/src/lib/o11y/api-metrics.server.ts b/src/lib/o11y/api-metrics.server.ts
index 918d40bb8..89495d452 100644
--- a/src/lib/o11y/api-metrics.server.ts
+++ b/src/lib/o11y/api-metrics.server.ts
@@ -58,7 +58,7 @@ export function getTokensFromCompletionUsage(
 }
 
 export function getToolsAvailable(request: GatewayRequest): string[] {
-  if (!request.body.tools) return [];
+  if (!Array.isArray(request.body.tools)) return [];
 
   if (request.kind === 'responses') {
     return request.body.tools.map((tool): string => {