feat: add tool call params logging (#1863)

This will enable logging for tool params. The server side changes should
all be ready now.

parent pr: #1862

Author: yulunz

src/index.ts

@@ -254,6 +254,8 @@ export async function createMcpServer(
         } finally {
           void clearcutLogger?.logToolInvocation({
             toolName: tool.name,
+            params,
+            schema,
             success,
             latencyMs: bucketizeLatency(Date.now() - startTime),
           });

src/telemetry/ClearcutLogger.ts

@@ -17,6 +17,7 @@ import {
   type FlagUsage,
   WatchdogMessageType,
   OsType,
+  type ToolInvocation,
 } from './types.js';
 import {WatchdogClient} from './WatchdogClient.js';
 
@@ -207,18 +208,27 @@ export class ClearcutLogger {
 
   async logToolInvocation(args: {
     toolName: string;
+    params: ShapeOutput<zod.ZodRawShape>;
+    schema: zod.ZodRawShape;
     success: boolean;
     latencyMs: number;
   }): Promise<void> {
+    const tool_invocation: ToolInvocation = {
+      tool_name: args.toolName,
+      success: args.success,
+      latency_ms: args.latencyMs,
+    };
+    if (Object.keys(args.params).length > 0) {
+      tool_invocation.tool_params = {
+        [`${args.toolName}_params`]: sanitizeParams(args.params, args.schema),
+      };
+    }
+
     this.#watchdog.send({
       type: WatchdogMessageType.LOG_EVENT,
       payload: {
         mcp_client: this.#mcpClient,
-        tool_invocation: {
-          tool_name: args.toolName,
-          success: args.success,
-          latency_ms: args.latencyMs,
-        },
+        tool_invocation: tool_invocation,
       },
     });
   }

src/telemetry/types.ts

@@ -22,6 +22,7 @@ export interface ToolInvocation {
   tool_name: string;
   success: boolean;
   latency_ms: number;
+  tool_params?: object;
 }
 
 export interface ServerStart {

tests/telemetry/ClearcutLogger.test.ts

@@ -46,6 +46,8 @@ describe('ClearcutLogger', () => {
       });
       await logger.logToolInvocation({
         toolName: 'test_tool',
+        params: {},
+        schema: {},
         success: true,
         latencyMs: 123,
       });
@@ -57,6 +59,40 @@ describe('ClearcutLogger', () => {
       assert.strictEqual(msg.payload.tool_invocation?.success, true);
       assert.strictEqual(msg.payload.tool_invocation?.latency_ms, 123);
     });
+    it('sends sanitized params', async () => {
+      const logger = new ClearcutLogger({
+        persistence: mockPersistence,
+        appVersion: '1.0.0',
+        watchdogClient: mockWatchdogClient,
+      });
+
+      const schema = {
+        uid: zod.string(),
+        myString: zod.string(),
+      };
+
+      const params = {
+        uid: 'sensitive',
+        myString: 'hello',
+      };
+
+      await logger.logToolInvocation({
+        toolName: 'test_tool',
+        params,
+        schema,
+        success: true,
+        latencyMs: 123,
+      });
+
+      assert(mockWatchdogClient.send.calledOnce);
+      const msg = mockWatchdogClient.send.firstCall.args[0];
+      assert.strictEqual(msg.type, WatchdogMessageType.LOG_EVENT);
+      assert.deepStrictEqual(msg.payload.tool_invocation?.tool_params, {
+        test_tool_params: {
+          my_string_length: 5,
+        },
+      });
+    });
   });
 
   describe('setClientName', () => {