feat(tools): extend cancellation to browser, web, and process tools

src/tools/builtin/web-fetch.ts

@@ -1,7 +1,7 @@
 import { parseHTML } from 'linkedom';
 import { Readability } from '@mozilla/readability';
 import TurndownService from 'turndown';
-import type { Tool, ToolResult } from '../types.js';
+import type { Tool, ToolExecutionContext, ToolResult } from '../types.js';
 
 // ---------------------------------------------------------------------------
 // Types
@@ -181,11 +181,15 @@ export const webFetchTool: Tool = {
     required: ['url'],
   },
 
-  execute: async (rawArgs: unknown): Promise<ToolResult> => {
+  execute: async (rawArgs: unknown, context?: ToolExecutionContext): Promise<ToolResult> => {
     const args = rawArgs as WebFetchArgs;
     const format: OutputFormat = args.format ?? 'markdown';
     const timeout = args.timeout ?? 15_000;
 
+    if (context?.signal?.aborted) {
+      return { success: false, output: '', error: 'Operation aborted' };
+    }
+
     // ----- Check cache (lazy eviction) ----- //
     evictExpired();
     const key = cacheKey(args.url, format);
@@ -196,8 +200,13 @@ export const webFetchTool: Tool = {
 
     // ----- Fetch ----- //
     try {
+      const timeoutSignal = AbortSignal.timeout(timeout);
+      const signal = context?.signal
+        ? AbortSignal.any([context.signal, timeoutSignal])
+        : timeoutSignal;
+
       const response = await fetch(args.url, {
-        signal: AbortSignal.timeout(timeout),
+        signal,
         headers: {
           'User-Agent': 'Flynn/0.1 (personal AI assistant)',
           Accept: 'text/html, application/json, text/plain, */*',
@@ -224,6 +233,9 @@ export const webFetchTool: Tool = {
 
       return { success: true, output };
     } catch (error) {
+      if (error instanceof Error && (error.name === 'AbortError' || error.message.toLowerCase().includes('aborted'))) {
+        return { success: false, output: '', error: 'Operation aborted' };
+      }
       return {
         success: false,
         output: '',