Borrowing it
Nothing to install: this file belongs to railsblueprint/blueprint-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/railsblueprint/blueprint-mcp/main/CLAUDE.mdgit clone --depth 1 https://github.com/railsblueprint/blueprint-mcpWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/railsblueprint/blueprint-mcp/claude-md)<a href="https://agentmods.dev/instructions/railsblueprint/blueprint-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/railsblueprint/blueprint-mcp/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/railsblueprint/blueprint-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/railsblueprint/blueprint-mcp/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.03161 | $0.03161 |
| Opus 5.5 | $0.01264 | $0.01264 |
| Sonnet 5.5 | $0.00632 | $0.00632 |
| Haiku 4.5 | $0.00316 | $0.00316 |
Grade A, and why
blueprint-mcp CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 371 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
Note: This project uses bd (beads) for issue tracking. Use bd commands instead of markdown TODOs. See AGENTS.md for workflow details.
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
Project Overview
Blueprint MCP for Chrome is an MCP (Model Context Protocol) server + browser extensions that allow AI applications to automate the user's existing browser session. Unlike typical browser automation tools, this project uses the user's real browser profile to maintain logged-in sessions and avoid bot detection.
Current Version: 1.5.5 Total Features: 200+ Total Commits: 599+
Supported Browsers:
- ✅ Chrome - TypeScript extension (4,000 lines + build step)
- ✅ Firefox - Vanilla JS extension (2,000 lines, no build)
- ✅ Opera - Uses Chrome source code (Chromium-based)
- 🚧 Safari - Planned (will share vanilla JS code with Chrome rewrite)
Key Features:
- Fast local automation without network latency
- Private - browser activity stays on device (Free tier)
- Cloud relay with OAuth2 (PRO tier)
- Uses existing browser profile and logged-in sessions
- Stealth mode - uses real browser fingerprint to avoid bot detection
- Tech stack detection - Auto-detects 40+ frameworks/libraries
- Auto-reconnection - Survives browser/extension reloads
Credits: Originally inspired by Microsoft's Playwright MCP, but completely rewritten for Chrome extension-based automation
Development Commands
Server Development
cd server
# Run MCP server in debug mode
node cli.js --debug
# Run with custom log file and port
node cli.js --debug --log-file ../logs/custom.log --port 5556
# Test the server
npm test
# Version bump and release (from root)
cd ..
./release.sh
Chrome Extension Development (TypeScript + Vite)
cd extensions/chrome
# Install dependencies
npm install
# Build extension
npm run build
# Watch mode for development
npm run dev
# Load unpacked extension from extensions/chrome/dist/
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 2mo ago First seen · 371 lines · 3,161 tokens per session scan A 9029c4280645
blueprint-mcp CLAUDE.md is an instructions file published in the GitHub repository railsblueprint/blueprint-mcp (106 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 3,161 tokens to every session, about $0.0126 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
blueprint-mcp CLAUDE.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| blueprint-mcp CLAUDE.mdrailsblueprint/blueprint-mcp | Instructions file | 106 | 2mo ago | Apache-2.0 | A | 3,161 | Claude Code |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | yesterday | MIT | A | 7,461 | Codex, OpenCode |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | yesterday | MIT | A | 4,680 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 5,516 | GitHub Copilot |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | yesterday | MIT | A | 3,093 | GitHub Copilot |
| deepseek-harness AGENTS.mddeepseek-ai/deepseek-harness | Instructions file | 274k | 2d ago | MIT | A | 4,313 | Codex, OpenCode |