silicon-browser

The most reliable browser for your AI agent.

Silicon Browser is a stealth-first, terminal-native headless browser CLI built for AI agents. It uses CloakBrowser's patched Chromium binary (33 C++ source-level patches) as its default browser engine, combined with the ref-based interaction model of agent-browser and 18 additional JavaScript-level stealth evasions for defense-in-depth.

Two layers of stealth. Zero configuration.

Why Silicon Browser?

Regular headless browsers get flagged by Cloudflare, DataDome, PerimeterX, and every other anti-bot system within milliseconds. Silicon Browser fixes this at two levels:

Layer 1: CloakBrowser (C++ binary-level patches)

• 33 Chromium source patches compiled into the binary -- not JS injection
• TLS fingerprints (JA3/JA4) naturally match real Chrome
• Canvas, WebGL, Audio fingerprints spoofed at the engine level
• CDP input signals eliminated -- programmatic input looks like hardware input
• navigator.webdriver removed at the C++ level
• Random fingerprint seed per session (--fingerprint=<seed> for persistence)

Layer 2: JavaScript stealth evasions (defense-in-depth)

On top of CloakBrowser's binary patches, 18 additional JS evasions are injected:

• navigator.webdriver -> false (prototype-level patching)
• Realistic plugin array (5 Chrome plugins)
• WebGL vendor/renderer masking (no more SwiftShader detection)
• Canvas & AudioContext fingerprint noise
• Proper window.chrome object with runtime, loadTimes, csi
• CDP artifact removal (cdc_*, $cdc_* properties)
• WebRTC IP leak prevention
• Realistic HTTP headers (Sec-Ch-Ua, Sec-Fetch-*, Accept)
• Default Chrome 131 user-agent string
• Screen/window dimensions matching real monitors (1920x1080)
• navigator.connection, hardwareConcurrency, deviceMemory
• Permissions API, Notification.permission patching
• ...and more

All stealth features are on by default. No configuration needed.

Quick Start

# Install
npm install -g silicon-browser

# Download Chrome
silicon-browser install

# Browse the web
silicon-browser open https://example.com
silicon-browser snapshot -i          # get interactive elements
silicon-browser click @e3            # click by ref
silicon-browser fill @e5 "query"     # fill input
silicon-browser screenshot           # capture screenshot

How It Works

Silicon Browser uses a ref-based interaction model -- instead of fragile CSS selectors, every interactive element gets a deterministic ref like @e1, @e2, etc:

$ silicon-browser snapshot -i
@e1  link "Home"
@e2  button "Sign In"
@e3  input "Search..."
@e4  link "About"

$ silicon-browser click @e2

This reduces context usage by up to 93% compared to screenshot-based approaches.

Stealth Architecture

Silicon Browser applies stealth at four layers:

1. CloakBrowser Binary (primary)

A patched Chromium with 33 C++ source-level modifications. Since it IS a real Chromium binary, TLS fingerprints, HTTP/2 settings, and browser internals all match real Chrome. silicon-browser install downloads it automatically.

2. Chrome Launch Flags

Anti-automation flags are injected at Chrome startup:

• --disable-blink-features=AutomationControlled
• --fingerprint=<random> (CloakBrowser deterministic fingerprint seed)
• --webrtc-ip-handling-policy=disable_non_proxied_udp
• --enable-gpu-rasterization
• --disable-infobars

3. JavaScript Injection

18 stealth evasions run via Page.addScriptToEvaluateOnNewDocument before any page code executes -- defense-in-depth on top of CloakBrowser's binary patches.

4. Network Headers

Realistic HTTP headers are set via CDP's Network.setExtraHTTPHeaders, including Client Hints (Sec-Ch-Ua), Fetch metadata, and proper Accept headers.

Configuration

Stealth (on by default)

# Disable stealth (for debugging)
SILICON_BROWSER_NO_STEALTH=1 silicon-browser open https://example.com

# Pin fingerprint seed (same identity across sessions)
SILICON_BROWSER_FINGERPRINT=42069 silicon-browser open https://example.com

# Custom user agent
silicon-browser --user-agent "Mozilla/5.0 ..." open https://example.com

# With proxy
silicon-browser --proxy "http://user:pass@proxy:8080" open https://example.com

Profiles (like a real person's browser)

Every profile has its own cookies, history, and pinned fingerprint seed -- the same profile always looks like the same person to websites.

# Default profile is "silicon" — always there, ready to go
silicon-browser open https://example.com

# Named profiles for different identities
silicon-browser --profile work open https://example.com
silicon-browser --profile personal open https://github.com

# Incognito — throwaway session, random fingerprint, no traces
silicon-browser --incognito open https://example.com

# Profiles stored at ~/.silicon-browser/profiles/<name>/
# Each profile has its own fingerprint.seed file
ls ~/.silicon-browser/profiles/
# silicon/  work/  personal/

Sessions

# Named sessions (multiple daemons in parallel)
silicon-browser --session work open https://example.com
silicon-browser --session personal open https://other.com
silicon-browser session list

Cloud Providers

silicon-browser -p browserbase open https://example.com
silicon-browser -p browserless open https://example.com

All Commands

| Command | Description | |---------|-------------| | open <url> | Navigate to URL | | snapshot | Get accessibility tree (add -i for interactive only) | | click @ref | Click element by ref | | fill @ref "text" | Fill input field | | type "text" | Type text (keystroke-level) | | screenshot | Capture screenshot | | get text @ref | Extract text from element | | get html @ref | Get HTML of element | | get value @ref | Get input value | | evaluate "js" | Execute JavaScript | | scroll down | Scroll the page | | select @ref "value" | Select dropdown option | | hover @ref | Hover over element | | tabs | List open tabs | | tab new <url> | Open new tab | | tab select <n> | Switch to tab | | close | Close browser | | install | Download Chrome |

Environment Variables

| Variable | Description | |----------|-------------| | SILICON_BROWSER_NO_STEALTH | Set to 1 to disable stealth features | | SILICON_BROWSER_FINGERPRINT | Pin fingerprint seed for CloakBrowser (consistent identity) | | SILICON_BROWSER_USER_AGENT | Default user agent string | | CLOAKBROWSER_BINARY_PATH | Use a custom CloakBrowser binary path | | CLOAKBROWSER_CACHE_DIR | Custom CloakBrowser cache directory | | CLOAKBROWSER_DOWNLOAD_URL | Custom CloakBrowser download server | | SILICON_BROWSER_PROXY | Default proxy URL | | SILICON_BROWSER_SESSION | Default session name | | SILICON_BROWSER_IDLE_TIMEOUT_MS | Auto-shutdown after inactivity | | SILICON_BROWSER_SOCKET_DIR | Custom socket directory |

Building from Source

# Prerequisites: Rust toolchain
git clone https://github.com/unlikefraction/silicon-browser.git
cd silicon-browser
cargo build --release --manifest-path cli/Cargo.toml

# The binary is at cli/target/release/silicon-browser

Credits

Silicon Browser builds on the excellent work of:

• agent-browser by Vercel -- the ref-based browser automation CLI
• CloakBrowser -- anti-detection browser techniques
• puppeteer-extra-plugin-stealth -- JS-level evasion patterns

License

Apache-2.0