Pagerunner — The Browser Layer That Learns

Pagerunner

A Chrome browser automation MCP server. Connect Claude (or any MCP client) to a real Chrome session — using your existing profiles with their cookies, saved passwords, and history.

[!WARNING] Pagerunner is early-stage software (v0.x). APIs and configuration formats may change between releases.

Contents

• How it works
• Setup
• Using with your project
• Tools
• Site Intelligence
• Session Checkpoints
• macOS Menu Bar App
• Anonymization (PII protection)
• Stealth mode
• Daemon (multiple Claude Code sessions / persistent state)
• Snapshots
• Example session
• Legal & Responsible Use

How it works

Pagerunner launches Chrome with your existing user profile via CDP (Chrome DevTools Protocol) and exposes it as an MCP server over stdin/stdout. Claude can then navigate, click, type, screenshot, and run JavaScript in the live browser.

Setup

1. Install

# Option A — Homebrew (easiest on macOS/Linux):
brew tap enreign/pagerunner
brew install pagerunner

# Option B — Cargo (if you have Rust):
cargo install pagerunner
# Note: if you get "requires rustc 1.91+" despite having a newer Rust installed,
# Homebrew's Rust may be shadowing rustup's. Fix: export PATH="$HOME/.cargo/bin:$PATH"

# Option C — Pre-built binary (no dependencies):

# macOS arm64 (Apple Silicon):
curl -L https://github.com/Enreign/pagerunner/releases/latest/download/pagerunner-macos-arm64 \
  -o pagerunner && chmod +x pagerunner

# macOS x86_64 (Intel):
curl -L https://github.com/Enreign/pagerunner/releases/latest/download/pagerunner-macos-x86_64 \
  -o pagerunner && chmod +x pagerunner

# Linux x86_64:
curl -L https://github.com/Enreign/pagerunner/releases/latest/download/pagerunner-linux-x86_64 \
  -o pagerunner && chmod +x pagerunner

# macOS: if Gatekeeper blocks the binary on first run:
xattr -d com.apple.quarantine pagerunner

# Option B — install via cargo (requires Rust):
cargo install --git https://github.com/Enreign/pagerunner --locked

# Option C — build locally:
cargo build --release

2. Auto-detect Chrome profiles

pagerunner init

This reads Chrome's profile list and writes ~/.pagerunner/config.toml automatically. Run pagerunner status to verify.

Alternatively, write ~/.pagerunner/config.toml by hand — see pagerunner example-config for the format.

3. Register as MCP server

# If installed (Options A or B — binary is in PATH):
claude mcp add pagerunner "$(which pagerunner)" mcp

# If built locally (Option C):
claude mcp add pagerunner "$(pwd)/target/release/pagerunner" mcp

For Claude Desktop, add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "pagerunner": {
      "command": "/absolute/path/to/pagerunner",
      "args": ["mcp"]
    }
  }
}

Note: The mcp subcommand is required — registering just the binary path without mcp will not work.

Note: Chrome locks profile directories. Close any Chrome window using a profile before opening a Pagerunner session on it.

4. Set up in your project (optional)

In any project directory with a CLAUDE.md or AGENTS.md:

pagerunner init

Pagerunner prints a ready-to-use usage snippet and offers to append it to your project file automatically. For scripting: pagerunner init --json.

5. (Optional, --features ner builds only) Download the NER model

pagerunner download-model   # ~65MB, enables PERSON/ORG name detection

Using with your project

Copy the example agent instructions into your project root so Claude (or any agent) immediately knows how to use Pagerunner:

# Claude Code projects:
curl -sL https://raw.githubusercontent.com/Enreign/pagerunner/main/docs/examples/CLAUDE.md -o CLAUDE.md

# Other agents (Gemini, Codex, etc.):
curl -sL https://raw.githubusercontent.com/Enreign/pagerunner/main/docs/examples/AGENTS.md -o AGENTS.md

Or paste the content manually and extend it with project-specific instructions.

Using Pagerunner with Claude Code

For comprehensive guidance, workflows, and examples tailored to 4 different use cases, install the Pagerunner Skill:

# Install the skill (once available in skills.sh registry)
claude skill install pagerunner-skill

Or explore the skill repository directly: pagerunner-skill

The skill includes:

• Quick starts for 4 ICPs: Solo Developer, Power User, Security-Conscious, Server-Side
• 11 workflow patterns: form filling, authentication, scrolling, multi-step interactions
• Complete reference: all 38 tools with parameters and examples
• Security guide: PII anonymization, audit logging, encryption
• Real-world examples: end-to-end workflows with error handling
• Troubleshooting: common issues and solutions

Start with the skill's SKILL.md to find your use case and quick start path.

Tools

Sessions & tabs

Navigation & content

Interactions

Snapshots & tab state

Key-value store

Network & console

Site intelligence

Session checkpoints

Site Intelligence

Pagerunner learns about sites as you use them and can call site APIs directly using your session credentials — no separate auth setup required.

Adapters are short JS functions stored in the encrypted DB and executed in the browser tab. Use them to call APIs that a site exposes (typically the same API the web UI uses):

register_adapter(origin="https://github.com", name="list-issues",
  description="List open issues for a repo",
  js_code="async ({owner, repo}) => { const r = await fetch(...); return r.json() }")

call_site_api(session_id, target_id, origin="https://github.com",
  name="list-issues", params={"owner": "Enreign", "repo": "pagerunner"})

Seed adapters for GitHub, Linear, Jira, Notion, and Gmail are built in.

Auth token detection — Bearer tokens, API keys, and session cookies discovered in network traffic are stored in the encrypted site vault. Adapters automatically have access to them via the credentials argument.

Selector stability — click, fill, and select track success/failure rates per selector. A fragility warning appears in the tool response when a selector fails >30% of the time over ≥5 uses.

Session Checkpoints

Save complete browser state (all open tabs with URLs and scroll positions) and restore it in any future session:

save_session_checkpoint(session_id, name="before-review")
  → checkpoint_id: cp_abc123

restore_session_checkpoint(session_id, checkpoint_id="cp_abc123")
  → reopens all saved tabs at their stored URLs

Checkpoints are stored in the encrypted DB and scoped to a profile.

macOS Menu Bar App

A native Swift companion app lives at apps/menubar/. It shows all Chrome profiles, active sessions, open tabs, and daemon status from the menu bar — no terminal required.

Features:

• One-click open/close sessions and save checkpoints
• Agent profiles shown with a distinct CPU icon in a separate section
• Add Profile flow: discovers unconfigured Chrome profiles or creates new agent profiles
• macOS native notifications: daemon stopped, session crashed, checkpoint saved
• Global hotkey and auto-update via Sparkle 2.x

Build and run:

pagerunner daemon &
cd apps/menubar
bash scripts/package.sh   # builds + bundles into scripts/Pagerunner.app
open scripts/Pagerunner.app

Anonymization (PII protection)

Pass anonymize: true to open_session to strip PII from all get_content and evaluate results before they reach Claude. Screenshots are blocked in anonymization mode.

{ "tool": "open_session", "profile": "personal", "anonymize": true }

Detected by default: EMAIL, PHONE, CREDIT_CARD, IBAN, SSN, IP With --features ner build: also detects PERSON and ORG names via a local ONNX model

Modes

• tokenize (default): replaces PII with tokens like [EMAIL:a3f9b2]. Pass tokens back to fill/type_text — Pagerunner de-tokenizes before writing to the DOM.
• redact: one-way replacement with [EMAIL] — no vault, no de-tokenization.

NER setup (PERSON and ORG name detection)

# 1. Build with NER support:
cargo build --release --features ner

# 2. Download the model (one-time, ~65MB):
pagerunner download-model

Disable globally in ~/.pagerunner/config.toml:

[ner]
enabled = false

Stealth mode

Pass stealth: true to open_session to enable anti-detection: hides automation signals, injects scripts to mask navigator.webdriver, and adds human-like delays between inputs.

{ "tool": "open_session", "profile": "personal", "stealth": true }

Example session

open_session(profile="personal")          → session_id: abc123
new_tab(session_id, url="https://...")    → target_id: TAB456
get_content(session_id, target_id)        → "page text..."
click(session_id, target_id, "#button")
type_text(session_id, target_id, "hello", selector="#input")
screenshot(session_id, target_id)         → "data:image/png;base64,..."
close_session(session_id)

Daemon (multiple Claude Code sessions / persistent state)

By default each pagerunner mcp process opens the database directly — only one can run at a time. If you open Pagerunner in a second Claude Code window you'll hit a DB lock error.

Start the daemon once to share state across any number of sessions:

pagerunner daemon &

Each pagerunner mcp instance automatically detects the daemon, connects to it over a Unix socket (~/.pagerunner/daemon.sock), and proxies all tool calls through it. All Claude Code windows share the same open browsers, KV store, and snapshots.

To stop:

pkill -f "pagerunner daemon"

Install as a background service (starts at login, restarts on crash):

./scripts/install-launchd.sh

The script detects your installed pagerunner binary automatically. Logs at ~/.pagerunner/daemon.log.

Note: After installing the daemon service, restart Claude Code. On the next launch, the daemon starts first (via launchd) and the MCP server connects to it in proxy mode. If Claude Code is already running when you install the daemon, you need two restarts: one to let launchd start the daemon, and one for the MCP server to reconnect to it.

Snapshots

Save authenticated browser state to the encrypted local DB:

save_snapshot(session_id, target_id, origin="https://github.com")

Restore it in any future session:

restore_snapshot(session_id, target_id, origin="https://github.com")

Snapshots are encrypted with AES-256-GCM. The key is stored in macOS Keychain under pagerunner / db_key — never written to disk in plaintext.

Legal & Responsible Use

Pagerunner automates a browser you own, using your own credentials. You are responsible for complying with the Terms of Service of any website you automate, applicable data protection laws (GDPR, CCPA), and authorized-access requirements (CFAA and equivalents).

Using anonymize: true is recommended for any workflow that involves processing personal data belonging to other people.

See DISCLAIMER.md for the full legal disclaimer, limitation of liability, and responsible use obligations.

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