offprompt MCP ServerVerifiedFeatured

What is offprompt?

offprompt is an open-source (MIT) MCP server that keeps API keys out of your AI agent's context. When Claude Code, Cursor, Codex or any MCP client needs a secret, it asks offprompt. A page opens in your browser on 127.0.0.1, you type or paste the value there, and offprompt writes it straight into .env.local. The transcript, the model's context and the provider's logs only ever see the key's name.

How to use offprompt?

Run npx offprompt init in your project (Node 22 or later). It detects your agents and adds the MCP server for them. To add it by hand, use:

{"mcpServers":{"offprompt":{"command":"npx","args":["-y","offprompt","mcp"]}}}

Then ask your agent to do something that needs a key, for example "add Stripe webhooks". It calls collect_secret, the page opens, and you fill it in.

Key features

• Values never enter the chat. The agent gets the key names and a fingerprint back, never the value.
• Local page on 127.0.0.1. Nothing is sent to a third party, and the page loads no remote code.
• 65 provider formats. Stripe, OpenAI, Anthropic, AWS, Supabase and more are checked as you type, so the wrong key is caught before it's written.
• Works in cloud sandboxes. Inside a remote sandbox it reaches your browser through a Cloudflare quick tunnel.
• Three tools: collect_secret, await_secret and cancel_secret.

Use cases

• Give Claude Code, Cursor or Codex a new API key without pasting it into the chat.
• Set up a project's .env with several keys in one go.
• Hand keys to an agent running in a cloud sandbox.