Polar's plugin for AI coding agents. It connects your agent to Polar, the open-source payment infrastructure platform, so it can set up products, checkouts, customer portals and webhooks in your app, test them against the Polar sandbox, and help you migrate from another payment provider.
The skills follow the Agent Skills format, so they also work in agents that don't support plugins.
| Server | URL | Use it for |
|---|---|---|
polar |
https://mcp.polar.sh/mcp/polar-mcp |
Your live Polar organization |
polar-sandbox |
https://mcp.polar.sh/mcp/polar-sandbox |
Test data on sandbox.polar.sh |
Both servers use OAuth. Nothing connects until you sign in to Polar and authorize an organization.
| Skill | What it does |
|---|---|
setup-polar |
Guided setup from scratch: connects the MCP server, creates an organization and a first product, then hands off to polar-integration. |
polar-integration |
Adds Checkout, Customer Portal and Webhooks endpoints with @polar-sh/sdk to any TS/JS framework, including Next.js, Express, Hono, Astro, SvelteKit, Remix, Nuxt and Cloudflare Workers. |
polar-testing |
Tests an integration against the sandbox: test cards, local webhooks with the Polar CLI (polar webhook listen, polar webhook trigger), mocks and CI. |
polar-migration |
Guides a migration to Polar: Polar's assisted migration from Stripe Billing, or recreating the catalog and moving customers from Paddle, Lemon Squeezy and others. |
/plugin install polar --marketplace polarsource/agent-toolkit
Then run /mcp, select polar or polar-sandbox and sign in to Polar in your browser. Skills are available as /polar:setup-polar, /polar:polar-integration and so on, and Claude also uses them on its own when a task matches.
codex plugin marketplace add polarsource/agent-toolkit
codex plugin add polar@polarThen sign in to Polar in your browser with codex mcp login polar or codex mcp login polar-sandbox. Codex uses the skills on its own when a task matches.
In Cursor, open Customize, choose From GitHub Repository and enter https://github.com/polarsource/agent-toolkit. Then sign in to polar or polar-sandbox from Cursor's MCP settings.
gemini extensions install https://github.com/polarsource/agent-toolkitThen sign in to Polar with /mcp auth polar or /mcp auth polar-sandbox.
agy plugin install https://github.com/polarsource/agent-toolkitThen sign in to polar or polar-sandbox from Antigravity's MCP settings.
Install the skills with skills:
npx skills add https://github.com/polarsource/agent-toolkitThen connect the MCP server by following the Polar MCP guide for your client.
- "Add Polar checkout and a webhook handler for my Pro plan to this Next.js app"
- "What's my MRR this month, and how does churn compare to last month?"
- "Why are customers canceling their subscriptions? Break it down by reason."
- "Send a sandbox
order.paidevent to my local webhook handler and check that it works" - "Create a 25% off launch discount for my yearly plan"
The plugin contains instructions and MCP server configuration only. It runs no scripts or hooks on your machine and sends no telemetry itself. The scripts in .github/ are for maintaining this repository, and the plugin never runs them.
When you use the MCP servers, your agent sends requests to mcp.polar.sh over HTTPS. They read and change data in the Polar organization you authorized, such as products, customers, subscriptions and orders, within the permissions you granted. To disconnect, clear the server's authentication in /mcp in Claude Code, run codex mcp logout <server> in Codex, or uninstall the plugin. Polar handles this data under its Privacy Policy and Terms of Service.
The skills also ask your agent to run commands and write code that talk to these services:
- Polar API (
api.polar.sh,sandbox-api.polar.sh): the integration code, tests and Polar CLI commands the skills set up call it with your own access token or CLI login. - Polar CLI telemetry (PostHog):
setup-polarandpolar-testinginstall the Polar CLI, which sends one anonymous event per command, such as the command name, duration, CLI version and OS. It never sends access tokens, organization IDs, URLs or payloads. Opt out withPOLAR_CLI_TELEMETRY_OPTOUT=1. - npm registry: to install
@polar-sh/cliand@polar-sh/sdk. - Your current payment provider (Stripe, Paddle or Lemon Squeezy):
polar-migrationmay read your existing billing code and data with your own API keys to map customers and products to Polar. Stripe migrations themselves run in Polar's dashboard.