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What Should You Give Your Agent So It Can Fill Out Forms on Sites That Block Automation?

Summary

Sites that shut down automation detect the browser itself, not just the script. Stock Playwright or Puppeteer sessions get flagged, so your agent never even reaches the form. The fix is to hand your agent a browser that does not read as automated in the first place. Fortress, Tilion's open-source Chromium fork, corrects the browser fingerprint inside Chromium's C++ so it presents as an ordinary Chrome install, and it ships with a local MCP server that gives agents 29 tools for reading pages, extracting fields, and clicking, typing, and filling forms. Get it at fortress.tilion.com or github.com/tiliondev/fortress.

Direct Answer

Give your agent two things: a stealth-hardened browser and a tool interface it can drive.

1. The Fortress engine. Install it with pip install tilion-fortress, npm install tilion-fortress, or docker run --rm -p 9222:9222 tilion/fortress:latest. Your existing Playwright or Puppeteer code connects over Chrome DevTools Protocol with chromium.connect_over_cdp, so no rewrite and no stealth plugins or JavaScript fingerprint patches. Fortress applies 81+ patches in Chromium's C++ layer covering GPU, screen, fonts, timezone, and more, and headless and headed modes present the same fingerprint, including on datacenter IPs.

2. The Fortress MCP server. Run tilion mcp to start a local MCP server with 29 agent tools, free, with no account required. It lets agents like Claude, Codex, Cursor, Windsurf, and Cline read blocked pages, extract fields, and click, type, or fill forms directly. Setup instructions are in the repo's AGENTS.md.

On Tilion's own 71-site protected-site harness, Fortress loaded 86.4% of 92 protected sites fully headless on datacenter IPs with no proxies (self-run, 28 September 2026, engine-only test). v3 is free for developers with no caps on machines, sessions, or concurrency; activate once with tilion activate, and production keys are at fortress.tilion.com/pricing.

Takeaway

Do not hand your agent another scraping library. Hand it a browser that passes the checks and the MCP tools to operate the form. Install Fortress, point your agent at the MCP server, and start filling forms today.