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Arson
Arson

Posted on • Originally published at gatesolve.dev

Solve CAPTCHAs in browser-use with MCP (Zero Custom Code)

#mcp #ai #browseruse #captcha

Your browser-use agent hits a Cloudflare Turnstile. Game over — unless you have a CAPTCHA solver wired in via MCP. Here is how to add one in 2 minutes with zero integration code.

The Problem

browser-use (83K+ stars) gives AI agents the ability to browse the web. But Cloudflare, Google, and hCaptcha detect automated browsers through CDP fingerprinting, binding injection, and hardware signals. Your agent's browser is flagged before the CAPTCHA even renders.

Stealth plugins help with basic bot detection, but CAPTCHAs are a different layer. The challenge is designed to block exactly what your agent is.

The Solution: MCP + Async Solver

Model Context Protocol (MCP) lets AI agents discover and use tools without custom integration code. GateSolve publishes an MCP server that exposes solve_captcha as a tool.

Agent detects CAPTCHA → calls solve_captcha via MCP → GateSolve solves in separate browser → token returned → agent continues
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The solve happens in a completely separate browser environment — different IP, different fingerprint, no CDP detection.

Setup: 2 Minutes

Step 1: Install 

npm install -g @gatesolve/mcp-server
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Step 2: Add to MCP Config 

{
  "mcpServers": {
    "gatesolve": {
      "command": "npx",
      "args": ["@gatesolve/mcp-server"],
      "env": {
        "GATESOLVE_API_KEY": "gs_your_key"
      }
    }
  }
}
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Step 3: There Is No Step 3

Your agent now has access to solve_captcha. When it encounters a CAPTCHA during browsing, the LLM calls the tool, receives a token, and injects it.

MCP vs Manual API

Manual approach:

import httpx, time
resp = httpx.post("https://gatesolve.dev/api/solve", json={
    "url": "https://example.com",
    "type": "turnstile",
    "sitekey": "0x4AAAA..."
}, headers={"Authorization": "Bearer gs_your_key"})
job_id = resp.json()["id"]
while True:
    result = httpx.get(f"https://gatesolve.dev/api/solve?id={job_id}",
        headers={"Authorization": "Bearer gs_your_key"})
    if result.json()["status"] == "completed":
        break
    time.sleep(2)
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MCP approach: One config file. The agent discovers and calls the tool automatically. No polling loop. No HTTP client. No auth header management.

Why Not Stealth Browsers?

Stealth browsers help avoid basic bot detection. But CAPTCHAs run behavioral analysis that stealth plugins cannot fake. More importantly, GateSolve solves the CAPTCHA in a completely separate environment with a clean fingerprint. Your agent just receives the token.

Supported Frameworks

Framework MCP Support Method
browser-use Native register_mcp_tools()
Claude Desktop Native config file
Cursor / Windsurf Native settings panel
n8n Via node MCP community node
Custom agents Any MCP client stdio or HTTP

Get Started

100 free solves per API key. No credit card required.

  1. Sign up at gatesolve.dev
  2. Get your API key
  3. Add the MCP config
  4. Your agent can now solve CAPTCHAs

Listed on the official MCP Registry as io.github.arsonx-dev/gatesolve-mcp.

Also published on gatesolve.dev/blog

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