Pirate Ship by Cotlet MCP server

Pirate Ship API and MCP server, self-hosted

A Pirate Ship API and a Pirate Ship MCP server you run on your own computer, in Python, on the session of your own Google Chrome. 51 of the 57 Pirate Ship tools we run in production at Cotlet: USPS and UPS rates, draft labels and batches, label downloads, SCAN Forms, shipments and tracking, reports, store order import, Ship From Addresses, Saved Packages, tracking emails and label settings. The six tools that spend or refund money are not in this version.

Pirate Ship has no public API and no official MCP server. This repo gives you both:

• MCP server for Claude Code, Claude Desktop, Cursor, Codex and any MCP client, over stdio or HTTP. Setup
• REST API on http://127.0.0.1:8787/api/v1/pirate-ship, with OpenAPI docs at /docs. Setup
• Python: call("getrates", tozip="10001", weight_oz=16), plus 11 ready scripts in examples/.

It is for technical people who want to run it themselves, for noncommercial use only (license). If you want it running 24/7 on a server, kept working when Pirate Ship changes its app, for a team or a business, use the hosted version at cotlet.dev.

git clone https://github.com/cotletdev/pirate-ship-api-mcp-server.git && cd pirate-ship-api-mcp-server
python3 -m venv .venv && . .venv/bin/activate && pip install -e .
pirate-ship-mcp connect                            # reads your Pirate Ship session from Chrome
pirate-ship-mcp call get_rates to_zip=10001 weight_oz=16
claude mcp add pirate-ship -- "$PWD/.venv/bin/pirate-ship-mcp" mcp

Contents

• How it works
• Requirements
• Install
• Connect your Chrome
• MCP server
• REST API
• Python and the example scripts
• All 51 tools
• Configuration
• Security and your Pirate Ship account
• Errors
• Self-hosted or hosted

How it works

AI agent (MCP) / script (REST, Python) ──▶ pirate-ship-mcp on your computer ──your cookies──▶ ship.pirateship.com
                                                     ▲
                       pirate-ship-mcp connect ──────┘ reads them once from your Chrome (DevTools Protocol)

1. You sign in to Pirate Ship in your own Chrome, the way you always do.
2. pirate-ship-mcp connect attaches to that Chrome through the Chrome DevTools Protocol, reads the pirateship.com cookies and Chrome's time zone, and saves them to ~/.config/pirate-ship-api-mcp/session.json, readable by your user only. It never sees or stores your password.
3. Every tool call is one of the GraphQL operations Pirate Ship's own web app sends to ship.pirateship.com/api/graphql, with those cookies, sent with curl_cffi, which copies Chrome's TLS fingerprint. No headless browser runs.

Pirate Ship's web app sends each operation as a persisted query: its name and the sha256 of the query text. The tools may send only the operations listed in operations.py, and account, password, payment method and identity operations are not on that list. When Pirate Ship changes one of the listed queries, the tool answers "Pirate Ship changed its app" until we record the new hash.

Shortened. The full README is on GitHub.