#!/usr/bin/env python3 """ PreToolUse hook: intercept WebFetch → suggest using tavily-extract instead """ import json import sys try: data = json.load(sys.stdin) url = data["tool_input"]["url"] except (KeyError, json.JSONDecodeError) as err: print(f"hook-error: {err}", file=sys.stderr) sys.exit(1) print(json.dumps({ "systemMessage": "WebFetch detected. AI is directed to use Tavily extract instead.", "hookSpecificOutput": { "hookEventName": "PreToolUse", "permissionDecision": "deny", "permissionDecisionReason": f"Please use mcp__tavily__tavily-extract with urls: ['{url}'] and extract_depth: 'advanced'" } }, separators=(',', ':'))) sys.exit(0)