AI Agent CAPTCHA Handling Guide: Why Multimodal Vision (VLM) Fails at Invisible Risk Control, and How to Break Through with API + MCP

As agent frameworks like Browser Use and LangGraph become popular, more teams try to use multimodal large models (VLM) to directly screenshot and click through CAPTCHAs. This article analyzes why the visual approach fails against modern invisible risk controls like Cloudflare Turnstile and reCAPTCHA v3 while consuming high inference costs, and provides a dual-track CAPTCHA handling architecture based on NexCaptcha hosted MCP and asynchronous API.