io.github.tiliondev/fortress MCP Server

<div align="center"> <img alt="Fortress" src="docs/assets/banner-fortress.png" width="100%">

One browser engine to rule them all

Stealth Chromium engine

<br/> <br/> <br/>

Fortress is a stealth Chromium engine that stops your scrapers and browser agents from getting blocked, with one line of code change. Bot detectors flag automation by reading the browser fingerprint; Fortress corrects that fingerprint inside Chromium's C++, so the browser presents as an ordinary Chrome install. Scrapers finish their runs, agents reach the pages they were sent to, and CreepJS, Sannysoft, BrowserScan, and live Cloudflare Turnstile all read it as human. Point your existing Playwright or Puppeteer at Fortress over CDP, and nothing else in your code changes.

_{Blink · V8 · BoringSSL patched in-tree · ANGLE / D3D11-backed WebGL · JA3/JA4-coherent TLS · monthly upstream rebase · reproducible, gauntlet-gated releases}

<table align="center"><tr> <td align="center" width="150"><h3>34</h3>_{single-surface<br/>C++ patches}</td> <td align="center" width="150"><h3>0%</h3>_{CreepJS<br/>headless / stealth}</td> <td align="center" width="160"><h3><code>[native&nbsp;code]</code></h3>_{across every<br/>realm}</td> <td align="center" width="150"><h3>BSD-3</h3>_{open engine,<br/>rebuild it yourself}</td> </tr></table> <p align="center"><img src="docs/assets/demo.gif" alt="Fortress clearing a live Cloudflare challenge, then passing sannysoft and BrowserScan" width="720"/></p>

_{<i>Unedited capture of the Fortress binary in a real window: it clears a live <b>Cloudflare</b> challenge, turns <b>bot.sannysoft.com</b> all green, then reads <b>BrowserScan</b> “Normal”. Reproduce with <code>tools/gauntlet.py</code>.</i>}

</div> <table> <tr> <td width="33%" valign="top">

Native-code parity

Every spoofed getter is a C++ getter: toString returns [native code], realm-invariant across main frame, iframes, and Web Workers.

</td> <td width="33%" valign="top">

Drop-in CDP

nodriver-style raw CDP on :9222, with no Runtime.enable leak. Keep Playwright, Puppeteer, or any CDP client; swap the browser, keep your code.

</td> <td width="33%" valign="top">

Clears the gauntlet

0% headless on CreepJS; Sannysoft, BrowserScan, and live Cloudflare Turnstile cleared, all as a stock Chrome install.

</td> </tr> <tr> <td width="33%" valign="top">

Auditable patches

34 small single-purpose diffs in patches/. Read one in a minute; rebuild the engine with one script.

</td> <td width="33%" valign="top">

Coherent by construction

Real V8, Blink, and BoringSSL keep engine, user-agent, and JA3/JA4 TLS shape in agreement: a Windows persona on a matching stack.

</td> <td width="33%" valign="top">

Tunable persona

One binary, a coherence-checked Windows identity; --uxr-* switches override any surface: GPU, screen, timezone, hardware, Client-Hints.

</td> </tr> </table>

---

What's new — 151.0.7908.0 · Engine Refresh

Released. Per-launch coherent personas, hardened.

• Per-locale keyboard (QWERTY / QWERTZ / AZERTY) · per-persona media devices · a full delivery-parity coherence pass.
• Platform ↔ GPU ↔ timezone ↔ language ↔ voices ↔ keyboard move as one coherent real device — on every launch, from a single binary.
• Native-code parity (toString() stays [native code]), realm-invariant (main / worker / iframe) — coherence compiled into the browser, not patched in JavaScript.

pip install -U tilion-fortress       # or:  docker run --rm -p 9222:9222 tilion/fortress:latest

→ full release notes

Contents

What it is · Quick start	what it is, install, first script, AI-agent setup
The Fortress MCP	29 stealth-browser tools for AI agents (Beta)
Why patch the engine, not the page	the self-revealing-JS thesis + the three detection layers
How Fortress compares	vs puppeteer-stealth · Camoufox · CloakBrowser · closed vendors
Proof: live-detector results	CreepJS / Sannysoft / BrowserScan / Cloudflare, with screenshots
Configure the persona	the --uxr-* fingerprint surface
Works with your stack	browser-use · Crawl4AI · Stagehand · LangChain
Build & verify	reproduce from source, verify provenance
Reference	troubleshooting · FAQ · roadmap · repo layout

---

What it is

Fortress is a Chromium fork that spoofs the browser fingerprint from inside the engine. The surfaces bot detectors read (canvas, WebGL, audio, fonts, navigator, and about thirty more) are corrected in Chromium's C++, with no JavaScript patch layer sitting on top for a page to catch.

It ships as an ordinary browser binary that exposes a CDP endpoint. Point Playwright, Puppeteer, or any CDP client at it and your existing automation runs unchanged.

A JavaScript stealth patch leaves an extra layer the page can find: .toString() shows the override's source, and re-grabbing the same primitive from an iframe or worker reaches past it. Fortress corrects the surface in the engine instead, so navigator.vendor resolves to the real C++ getter, reports [native code], and reads the same from every realm. A page inspecting itself sees stock Chromium. That is why your automation gets through where it used to get flagged, and whatever blocking is left traces to your proxies and behavior rather than the browser. Why patch the engine, not the page covers the detection mechanics in full.

from tilion_fortress import Fortress
from playwright.sync_api import sync_playwright

with Fortress() as f:                                   # launches the stealth engine on a CDP endpoint
    with sync_playwright() as p:
        browser = p.chromium.connect_over_cdp(f.cdp_url)
        page = browser.new_page()
        page.goto("https://bot.sannysoft.com")
        page.screenshot(path="all-green.png")

import { Fortress } from "tilion-fortress";
import { chromium } from "playwright";

const f = await Fortress.launch();                      // stealth engine on a CDP endpoint
const browser = await chromium.connectOverCDP(f.cdpUrl);
const page = await browser.newPage();
await page.goto("https://browserscan.net");
await browser.close();
await f.close();

<div align="center">

The 12-second tour

<img src="docs/assets/fortress-reel.gif" width="760" alt="Fortress in 12 seconds: passes CreepJS, Sannysoft, BrowserScan and rebrowser, scrapes real sites, and clears Akamai on aa.com, lowes.com, macys.com and kohls.com."/>

_{One loop, all real captures: passes <b>CreepJS / Sannysoft / BrowserScan / rebrowser</b> → scrapes structured data over CDP → clears <b>Akamai</b> on aa.com · lowes · macys · kohls (same residential IP).}

</div> <div align="center">

Real scraping, fully headless

_{Unedited captures of the Fortress engine driven over CDP. No stealth plugins, no JS patches: the fingerprint is corrected in the binary. Reproduce any of these with <a href="examples/scrape_demos.py"><code>examples/scrape_demos.py</code></a>.}

<img src="docs/assets/fortress-scrape-structured.gif" width="720" alt="Fortress extracting books.toscrape.com into typed JSON records live over CDP"/>

_{<b>Structured extraction</b>: records build into typed JSON as each item is read.}

<table><tr> <td align="center" width="50%"><img src="docs/assets/fortress-scrape-paginated.gif" width="358" alt="Fortress auto-paginating across pages of quotes.toscrape.com"/><br/>_{<b>Auto-pagination</b>: 30 quotes across 3 pages.}</td> <td align="center" width="50%"><img src="docs/assets/fortress-scrape-detail.gif" width="358" alt="Fortress deep-crawling a product detail page"/><br/>_{<b>Deep detail crawl</b>: UPC · price · tax · stock · reviews.}</td> </tr></table> </div> <div align="center">

Clears real Akamai — before / after

<img src="docs/assets/fortress-akamai.gif" width="760" alt="Before: a stock browser is blocked by Akamai on aa.com with Access Denied. After: Fortress loads the real page and Akamai's sensor accepts it."/>

_{Same residential IP, same site (<b>aa.com</b> · Akamai Bot Manager). A stock/headless browser gets <b>Access Denied</b> (Reference #); Fortress loads the real page and Akamai issues its <code>_abck</code> sensor cookie — the Bot Manager accepts it as a real browser. The variable is the <b>fingerprint</b>, not the IP.}

<table><tr> <td align="center" width="33%"><img src="docs/assets/fortress-akamai-lowes.gif" width="250" alt="Fortress clearing Akamai on lowes.com"/><br/>_{<b>lowes.com</b> · blocked → cleared}</td> <td align="center" width="33%"><img src="docs/assets/fortress-akamai-macys.gif" width="250" alt="Fortress clearing Akamai on macys.com"/><br/>_{<b>macys.com</b> · blocked → cleared}</td> <td align="center" width="33%"><img src="docs/assets/fortress-akamai-kohls.gif" width="250" alt="Fortress clearing Akamai on kohls.com"/><br/>_{<b>kohls.com</b> · blocked → cleared}</td> </tr></table>

_{Not a one-site fluke — same before/after on major Akamai-protected retailers, every run from the same residential IP.}

</div>

---

Quick start

# Python / Node: prebuilt native binary auto-fetched (Linux x64 & Windows x64), SHA-256 verified
pip install tilion-fortress
npm  install tilion-fortress

# Any OS via Docker: raw CDP on :9222  (~302 MB pull / 851 MB on disk, stripped single-layer)
docker run --rm -p 9222:9222 tilion/fortress:latest

# Portable bundle (extract-and-run, like a Chromium snapshot)
tar xzf tilion-fortress-linux-x64.tar.gz            # Linux
./tilion-fortress/tilion --headless=new --remote-debugging-port=9222 --user-data-dir=/tmp/p

# Debian / Ubuntu
sudo apt install ./tilion-fortress_151.0.7908.0_amd64.deb && tilion https://example.com

[!TIP] The SDK ships the compiled build plus patches/, so you can rebuild the engine yourself and verify every surface correction against the source. Downloads are SHA-256-verified against the release SHA256SUMS automatically.

Versions

Fortress ships on two Chromium bases — pick your trade-off between blend-in and currency:

Channel	Chromium	When to use
stable (default)	149	Recommended — matches the Chrome version the mass of real users run, so it blends in best
latest	151	Newest engine (reports a version slightly ahead of stable)

Fortress().start()                     # Python: stable (149) by default
Fortress(channel="latest").start()     # opt into 151

await Fortress.launch();               // Node: stable (149) by default
await Fortress.launch({ channel: "latest" });

docker run --rm -p 9222:9222 tilion/fortress:149   # or :151
# or set FORTRESS_CHANNEL=latest for either SDK

Native binaries: Linux x64 (both versions) + Windows x64 (151); Windows-149 and macOS run via the Docker image.

Drop it into your AI agent

Fortress is the browser your agent drives: raw CDP on :9222, no stealth plugins to wire up. There are two ways in.

Option 1: open it pre-loaded in a chat assistant. One click; it reads our AGENTS.md and walks you through the whole setup:

Option 2: Copy for agent (everything, to your clipboard). Hit the copy icon at the top-right of the box below. It puts the entire setup context on your clipboard: what it is, install, connect, persona, and rules, all of AGENTS.md condensed. Paste it into Cursor, Claude Code, Copilot, ChatGPT, or any agent and it takes it from there:

You're setting up Fortress, an open-source STEALTH Chromium engine, for browser automation.
It corrects the browser fingerprint (canvas, WebGL, audio, fonts, navigator, +30 more) in Chromium's
C++ and exposes raw CDP on http://localhost:9222, a drop-in for Playwright/Puppeteer. Do NOT add
puppeteer-stealth or any JS fingerprint patching (it self-reveals and undoes Fortress).

LAUNCH (pick one; all expose CDP on http://localhost:9222):
  Docker:  docker run -d --rm -p 9222:9222 tilion/fortress:latest
  Python:  pip install tilion-fortress    then  from tilion_fortress import Fortress; f=Fortress(); f.start()
  Node:    npm install tilion-fortress    then  import {Fortress} from "tilion-fortress"; const f=await Fortress.launch()

CONNECT (keep my existing automation code):
  Playwright(py):  browser = p.chromium.connect_over_cdp("http://localhost:9222")
  Playwright(js):  const browser = await chromium.connectOverCDP("http://localhost:9222")
  Puppeteer(js):   const browser = await puppeteer.connect({ browserURL: "http://localhost:9222" })
  browser-use / Crawl4AI / Stagehand / LangChain:  point their CDP endpoint at http://localhost:9222

PERSONA (optional; default is a coherent Windows identity). Override any surface with --uxr-* flags:
  --uxr-timezone=America/New_York --uxr-hw-concurrency=16 --uxr-languages=en-US,en

RULES:
  1) Drive over raw CDP (:9222); don't spawn chromedriver.
  2) Never pass --user-agent (use --uxr-ua-*); it desyncs UA vs UA-Client-Hints.
  3) No puppeteer-stealth / undetected-chromedriver / JS fingerprint patches.
  4) Blocked ~90% = my IP (datacenter), not the fingerprint. Use a residential/mobile proxy, then retry.

Now walk me through launching Fortress and wiring my automation to it.
Full guide: https://github.com/tiliondev/fortress/blob/main/AGENTS.md

---

The Fortress MCP — stealth browsing as agent tools  _Beta

Raw CDP is for code you write. The Fortress MCP is for agents that call tools: a Model Context Protocol server that hands Claude, Cursor, or any MCP client a stealth browser, so the moment a fetch is blocked it just calls a tool and gets the page. 29 tools, local and free — fetch_protected_page, extract_page, crawl_site, recon_site_apis, search_web, run_browser_task, save_profile, get_stealth_cdp_endpoint, and more.

<p align="center"><img src="mcp/demo.gif" alt="Same site, same prompt: a vanilla browser is blocked by PerimeterX while an agent with the Fortress MCP returns clean JSON" width="760"/></p>

_{<i>Real, dated run against <b>stockx.com</b> (PerimeterX). A stock browser gets <b>HTTP 403 — “Access denied”</b>; an agent with the Fortress MCP returns clean JSON — same site, same prompt. Reproduce it from the framework repo.</i>}

Set it up in 30 seconds

Two runners — pick one. npx needs Python on PATH; pip installs it directly:

pip install "tilion[mcp]"      # command:  tilion-mcp
#   —or, zero-install—
npx -y tilion-mcp              # auto-runs the server via uv (no global install)

Claude Desktop — Settings → Developer → Edit Config (claude_desktop_config.json):

{ "mcpServers": { "fortress": { "command": "tilion-mcp" } } }

_{Prefer npx? Use <code>"command": "npx", "args": ["-y", "tilion-mcp"]</code>. Restart Claude, and the <b>fortress</b> tools appear.}

Claude Code (CLI) — one line:

claude mcp add fortress -- tilion-mcp          # or:  claude mcp add fortress -- npx -y tilion-mcp

Cursor (~/.cursor/mcp.json) · Cline / Windsurf (VS Code → MCP servers) — same block:

{ "mcpServers": { "fortress": { "command": "tilion-mcp" } } }

Then just ask your agent — “get the price off this StockX page” — and it calls fetch_protected_page on its own.

What the agent gets

	tools
Get blocked pages	fetch_protected_page · read_page · get_page_html · search_web
Structured data	extract_page (schema-aware) · extract_document (PDF/DOCX/XLSX)
Whole sites	crawl_site (auto-SPA) · recon_site_apis (find the private JSON API)
Drive a page	page_elements · click_button · fill_field · press_key · wait_for · evaluate_js
Multi-step flows	run_browser_task (login, paginate, infinite-scroll, checkout, …)
Capture / auth	screenshot_page · save_page · download_file · save_profile / load_profile
Bring your own	get_stealth_cdp_endpoint → a CDP url for Playwright / Puppeteer / browser-use

Tools are annotated (reads auto-approve, writes gate), pre-warmed on startup (~100 ms first call), concurrency-safe, and timeout- and SSRF-guarded. A hosted endpoint with residential egress is coming soon.

→ Full 29-tool table, benchmarks, and the agent skill: mcp/

---

Why patch the engine, not the page

The usual approach patches navigator.webdriver, spoofs the WebGL vendor, and overrides navigator.plugins from script. CreepJS and similar detectors still flag it, and the reason is structural, not one more property left uncovered. A JavaScript spoof is a function standing where a native one belongs. Detectors set the returned value aside and interrogate whether the thing returning it is native:

The tell	Why it catches a JS spoof
toString self-reveal	A native method stringifies to function get vendor() { [native code] }; an override stringifies to its own source, so one .toString() catches it.
Descriptor and hasOwnProperty	getOwnPropertyDescriptor exposes redefined props, and hasOwnProperty('toString') returns true on a tampered function where a native one returns false.
failsTypeError	Native getters throw a specific TypeError on the wrong this; a naive shim stays quiet, and the silence is the signal.

Realm re-acquisition is the one that defeats every main-world patch. A detector grabs a pristine primitive from another realm and turns it on your function:

const iframe = document.createElement('iframe'); document.body.appendChild(iframe);
const realToString = iframe.contentWindow.Function.prototype.toString;
realToString.call(navigator.__lookupGetter__('vendor')); // returns your source code. Caught.

Your main-world patch lives in a different realm from that iframe. The same trap fires from a Web Worker, a thread your main-thread shim runs beside rather than inside.

Fortress has no such layer. The getter for navigator.vendor is the C++ getter: it reports [native code] because it is native code, identical across every realm. Camoufox puts it well: "there is no JavaScript hijacking to be detected." Fortress applies the same idea to V8 and Blink in place of Gecko.

The three layers of bot detection, and where Fortress fits

Modern anti-bots (Cloudflare, DataDome, Kasada, HUMAN, Akamai) read three structurally different surfaces, in three separate places. One tool rarely fixes all three:

Layer	The tells	Where the fix lives	Fortress
A: driver / binary artifacts	cdc_ ChromeDriver vars, WebDriver protocol surface	Drive raw CDP, skip chromedriver	<img src="docs/assets/icons/check.svg" width="15" alt="yes"> built to be driven this way
B: CDP side-effects	Runtime.enable leaks via sourceURL + init-script footprints, however clean the binary is	The control / CDP-client layer: hold back Runtime.enable, use Runtime.addBinding + isolated worlds	<img src="docs/assets/icons/check.svg" width="15" alt="yes"> no leak (verified)
C: fingerprint surface	canvas, WebGL, audio, fonts, navigator, across main frame, iframes, workers	The engine (C++), because JS overrides self-reveal	<img src="docs/assets/icons/check.svg" width="15" alt="yes"> this is Fortress

Fortress is the Layer-C engine, built to be driven so A and B hold too. The binary alone leaves the CDP channel open. That part is on the control layer, and pretending otherwise is how you get caught.

---

How Fortress compares

	Stock Playwright	puppeteer-extra-stealth	undetected-chromedriver	Camoufox	CloakBrowser	Fortress
Spoof layer	none	JS injection	CDP/config patch	C++ engine	C++ engine	C++ engine
toString yields [native code]	n/a	<img src="docs/assets/icons/x.svg" width="15" alt="no">	n/a	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">
Survives realm re-acquisition (iframe/worker)	<img src="docs/assets/icons/x.svg" width="15" alt="no">	<img src="docs/assets/icons/x.svg" width="15" alt="no">	<img src="docs/assets/icons/x.svg" width="15" alt="no">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">
No Runtime.enable leak	<img src="docs/assets/icons/x.svg" width="15" alt="no">	<img src="docs/assets/icons/x.svg" width="15" alt="no">	<img src="docs/assets/icons/warn.svg" width="15" alt="partial">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">
Engine = Chrome / V8 (majority traffic)	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/x.svg" width="15" alt="no"> Firefox	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">
Coherent Chromium TLS shape	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/x.svg" width="15" alt="no"> Firefox	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">
Fully open-source engine	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/warn.svg" width="15" alt="partial"> latest major paywalled	<img src="docs/assets/icons/check.svg" width="15" alt="yes">
Published, auditable patch series	n/a	n/a	n/a	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/warn.svg" width="15" alt="partial"> binary only	<img src="docs/assets/icons/check.svg" width="15" alt="yes">
Reproducible from-source build	n/a	n/a	n/a	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/x.svg" width="15" alt="no">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">
States its own limits	n/a	n/a	n/a	<img src="docs/assets/icons/check.svg" width="15" alt="yes">	<img src="docs/assets/icons/x.svg" width="15" alt="no">	<img src="docs/assets/icons/check.svg" width="15" alt="yes">

Fortress builds on real prior art: fingerprint-chromium, ChromiumFish, and CloakBrowser came first, and commercial vendors (Multilogin, Kameleo, GoLogin, AdsPower, Browserbase, Surfsky) recompile Chromium behind closed source. Most of that work stays closed: the paywalled forks hand you a binary and ask you to trust it, and the vendors keep their patches in-house.

Fortress goes the other way, because a stealth engine only stays useful when the people relying on it can see how it works. Every surface correction lives in patches/ as a small, single-purpose diff you can read in a minute, and the whole engine rebuilds from source with one script. When a detector finds a new tell, you trace the fix, patch it, and send it back. That feedback loop is the point, and it only works while the engine stays open enough to read, extend, and rebuild.

---

Proof: live-detector results

Reproduce any row with tools/gauntlet.py --bundle ./tilion-fortress. Verified against live detectors; re-run dated in docs/GAUNTLET_RESULTS.md.

Suite	Stock Chromium	Fortress
CreepJS	flagged headless	0% headless · 0% stealth, worker signals coherent
bot.sannysoft.com	red rows	0 failed · WebDriver Advanced passed · WebGL = NVIDIA RTX 3060 / ANGLE D3D11
browserscan.net	bot detected	“No bots detected, could be a human”
rebrowser bot-detector	Runtime.enable LEAK	no leak · webdriver=false · clean init-scripts (raw CDP)
Cloudflare Turnstile	blocked	bypassed: a human click cleared a live challenge (headed, datacenter IP)

<details open><summary><b>Proof: real, unedited screenshots</b></summary> <br/> <img src="docs/assets/sannysoft_top.png" width="680"/>

BrowserScan	CreepJS	Cloudflare
<img src="docs/assets/browserscan_top.png" width="240"/>	<img src="docs/assets/creepjs.png" width="240"/>	<img src="docs/assets/cloudflare_bypass.gif" width="240"/>

</details>

---

Configure the persona

The binary carries zero brand strings; the launcher applies a coherent default Windows persona. Override any surface with --uxr-* switches, or set TILION_NO_DEFAULTS=1 for a bare launch.

--uxr-platform / --uxr-ua-platform / --uxr-ua-os / --uxr-ua-arch / --uxr-ua-bitness
--uxr-ua-platform-version / --uxr-ua-brand / --uxr-hw-concurrency / --uxr-device-memory
--uxr-webgl-vendor / --uxr-webgl-renderer / --uxr-webgl-fullparams
--uxr-canvas-seed / --uxr-audio-seed / --uxr-timezone / --uxr-languages
--uxr-screen-width / --uxr-screen-height / --uxr-webrtc-policy=disable_non_proxied_udp

Env var	Purpose
TILION_NO_DEFAULTS=1	Skip the default persona (bare launch)
TILION_TZ / TILION_LANG	Quick timezone / language override

[!NOTE] The persona rides on the command line today. The --uxr-* switches are world-readable via /proc/<pid>/cmdline, so it's one persona per launch and visible to other processes on the host. The MaskConfig runtime lands next: it delivers the persona over IPC and lifts the one-per-process limit (see what's next).

---

Works with your stack

Fortress exposes raw CDP on :9222, so it drops in under anything that speaks Playwright, Puppeteer, or CDP.

Framework	Connect via
browser-use (~70k stars)	cdp_url="http://localhost:9222"
Crawl4AI (~58k stars)	CDP endpoint
Stagehand (~21k stars)	connectOverCDP
LangChain Playwright toolkit	Playwright CDP
Playwright / Puppeteer (Python & JS)	connect_over_cdp / connect

from playwright.sync_api import sync_playwright
with sync_playwright() as p:
    browser = p.chromium.connect_over_cdp("http://localhost:9222")   # Fortress under the hood

---

Build & verify

Reproduce from source

export CHROMIUM_VERSION=$(cat CHROMIUM_VERSION)
build/build.sh                         # depot_tools, sync the tag, apply patches, gn gen, ninja
build/rebase-monthly.sh 152.0.XXXX.0   # bump + 3-way apply + rebuild + gauntlet-gate

Output: out/Fortress/chrome. The fork is 34 small single-surface patches (patches/), so most re-apply cleanly across upstream releases; the gauntlet then gates the release on any regression.

Platform	Status
Linux x64 (native) · Windows x64 (native) · any OS via Docker	<img src="docs/assets/icons/check.svg" width="15" alt="yes"> shipping
Code-signed installers · macOS .app · linux/arm64	in progress

Verify it's really ours

Fortress ships from four official channels. Treat anything else as untrusted:

	Official source
Source	github.com/tiliondev/fortress
Docker	tilion/fortress
Python	tilion-fortress
Node	tilion-fortress

Verify a download. Every release ships SHA256SUMS, and the pip/npm SDKs run this for you on install:

BASE=https://github.com/tiliondev/fortress/releases/download/v151.0.7908.0
curl -LO $BASE/tilion-fortress-linux-x64.tar.gz
curl -Ls $BASE/SHA256SUMS | sha256sum -c --ignore-missing     # -> OK

Verify the Docker image by digest (not just the tag):

docker pull tilion/fortress:151.0.7908.0
docker inspect --format '{{index .RepoDigests 0}}' tilion/fortress:151.0.7908.0
# compare the printed sha256:... against the digest in the GitHub Release notes

Or trust nothing and rebuild it. The whole fork is 34 readable patches in patches/; build/build.sh reproduces the binary from Chromium source, so you can diff what you built against what we ship.

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Reference

<details><summary><b>Troubleshooting</b></summary> <br/>

Still blocked on Cloudflare, DataDome, or Kasada. Most of the time this is your IP, not your fingerprint: a datacenter range gets flagged before any page script runs. Route egress through residential or mobile proxies and retry; if it clears, the fingerprint was fine.

The fingerprint looks off on a Linux host. The default persona is Windows, but the TLS shape and some OS-facing signals follow the machine underneath. Match the persona to your egress OS, or set the relevant --uxr-* flags so the OS story agrees with where the traffic leaves from.

macOS pulls a Docker image. Native Linux + Windows binaries ship today; macOS still runs Fortress through the official Docker image (tilion/fortress). Install Docker Desktop, or run on Linux/Windows x64 for the native binary.

The persona shows up in /proc/<pid>/cmdline. The --uxr-* flags are readable by other processes on the host, one persona per launch. Until the runtime MaskConfig lands, keep one persona per process and avoid sharing the host with untrusted code.

A detector flags something the gauntlet passes. Detection moves. Confirm you're on the current Chromium rebase, then open an issue with the test page. That page becomes the next patch.

</details> <details><summary><b>FAQ</b></summary> <br/>

Is this legal? Fortress is a browser engineering project for legitimate automation, testing, and scraping of publicly available data. Respect each site's ToS and the law in your jurisdiction.

Is it really free? Yes. BSD-3, fully open, and self-hostable. The patch series is published, so you can build the current engine from source yourself.

Why not just use puppeteer-stealth or undetected-chromedriver? They patch the JS/CDP layer after the page can inspect the browser, so they self-reveal via toString and realm re-acquisition. Fortress moves the spoof into C++, where the page finds native code. (See "Why patch the engine, not the page.")

How is this different from Camoufox? Same C++-interception idea. Camoufox forks Firefox (~3% of traffic, a standing anomaly) while Fortress forks Chromium and V8 (the majority engine), so a Chrome user-agent is coherent by construction.

Will it pass everything forever? No. Detection keeps moving, so we ship a dated, reproducible gauntlet and a monthly Chromium rebase; you can always see exactly what passes today.

</details> <details><summary><b>Roadmap</b></summary> <br/>

• Runtime JSON config into a C++ MaskConfig (one binary, many coherent fingerprints, nothing on the command line)
• First-party MCP server plus Puppeteer / raw-CDP SDKs (drop-in for AI agents)
• Code-signed Windows .exe and macOS .app
• linux/arm64 Docker image
• Migrate patches/ to Brave-style chromium_src/ overrides
• Published reCAPTCHA v3 / DataDome / Kasada benchmark rows (dated, reproducible)

</details> <details><summary><b>Repo layout</b></summary>

patches/     34 per-surface C++ patches (+ series), the source of truth for the fork
build/       args.gn, build.sh, apply-patches.sh, rebase-monthly.sh, windows/, macos/
packaging/   tilion launcher, fonts.conf, Dockerfile, .deb + bundle builders
fonts/       33 metric-compatible Windows-named fonts (incl. color emoji)
sdk/         python + node (tilion-fortress) prebuilt-binary SDKs
tools/       gauntlet.py, the CreepJS / Sannysoft / BrowserScan CI gate
docs/        GAUNTLET_RESULTS, BUILD_NATIVE, BENCHMARK

</details>

Contributing

Found a detection vector or a leak we missed? Open an issue with a reproducible test page. A page that reliably flags Fortress is the most valuable thing you can send. It becomes the next patch. Two house rules: every capability claim ships with a command that reproduces it, and every limit is written down. The word "undetectable" stays out of the repo.

License

BSD-3-Clause for the Fortress patches and tooling (matching Chromium). Chromium and the bundled fonts retain their own licenses; see LICENSE and NOTICE. The patch series is published, so you can audit and rebuild the engine yourself.

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What's next

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[!IMPORTANT] v2: MaskConfig runtime personas. An IPC-delivered, seed-driven persona graph feeding a process-global C++ MaskConfig singleton: thousands of coherence-invariant fingerprints from a single binary, per-BrowserContext identity isolation, and zero command-line footprint. The rest is on the roadmap.

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Staying current

Detection keeps moving, so a stealth engine is only as good as its last rebase. Fortress tracks the latest Chromium monthly, re-runs the full gauntlet, and ships a patch whenever a detector finds a new tell, so what you run keeps matching what a real Chrome install looks like. Watch the releases to follow the v2 MaskConfig work, or star the repo if it's useful to you.

<em>Stealth you can read, rebuild, and run yourself.</em>

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