From d0e032057345d251f45c69925b0a318672c28bee Mon Sep 17 00:00:00 2001
From: Alex Rudenko <alexrudenko@chromium.org>
Date: Thu, 29 Jan 2026 14:29:35 +0100
Subject: [PATCH] fix: do not post telemetry entry for unsupported tools

---
 src/main.ts         | 16 +++++++++++-----
 tests/index.test.ts | 18 ++++++++++++++++++
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/src/main.ts b/src/main.ts
index 6ba8ddf41..858978d10 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -128,6 +128,8 @@ For more details, visit: https://github.com/ChromeDevTools/chrome-devtools-mcp#u
 
 const toolMutex = new Mutex();
 
+const toolNames = new Set<string>(tools.map(t => t.name));
+
 function registerTool(tool: ToolDefinition): void {
   if (
     tool.annotations.category === ToolCategory.EMULATION &&
@@ -222,11 +224,15 @@ function registerTool(tool: ToolDefinition): void {
           isError: true,
         };
       } finally {
-        void clearcutLogger?.logToolInvocation({
-          toolName: tool.name,
-          success,
-          latencyMs: bucketizeLatency(Date.now() - startTime),
-        });
+        if (toolNames.has(tool.name)) {
+          void clearcutLogger?.logToolInvocation({
+            toolName: tool.name,
+            success,
+            latencyMs: bucketizeLatency(Date.now() - startTime),
+          });
+        } else {
+          // TODO: unsupported tools?
+        }
         guard.dispose();
       }
     },
diff --git a/tests/index.test.ts b/tests/index.test.ts
index 5b3f7a54e..7c0278673 100644
--- a/tests/index.test.ts
+++ b/tests/index.test.ts
@@ -85,6 +85,24 @@ describe('e2e', () => {
     });
   });
 
+  it('reports errors for unknown tools', async () => {
+    await withClient(async client => {
+      const result = await client.callTool({
+        name: 'unknown_tool',
+        arguments: {},
+      });
+      assert.deepStrictEqual(result, {
+        content: [
+          {
+            type: 'text',
+            text: 'MCP error -32602: Tool unknown_tool not found',
+          },
+        ],
+        isError: true,
+      });
+    });
+  });
+
   it('has all tools', async () => {
     await withClient(async client => {
       const {tools} = await client.listTools();