An SDK that turns YAML into live MCP servers.

paso is an open-source SDK for Node.js and Python. You describe your API's capabilities in a single YAML file. paso generates a live MCP server from that declaration. AI agents connect to the server and interact with your API. No protocol code to write, no MCP SDK to learn.

Your service has value. The protocol layer shouldn't extract it.

There are 17 agent protocols today. MCP, A2A, function calling formats, agent cards. Each one wants its own server, its own SDK, its own maintenance burden. Every new protocol is a bet on someone else's roadmap.

We think there's a simpler model. Declare what your API can do, once. Let the infrastructure layer handle the protocol details. Today that's MCP. Tomorrow it's whatever the industry agrees on next. Your declaration doesn't change.

We believe the terms of participation in the agent economy should be set by the people who build the services, not by whoever controls the integration layer. Self-hosted. No cloud dependency. No vendor lock-in. Your server, your rules.

Apache 2.0. Built in the open.

paso is licensed under Apache 2.0. The code is on GitHub. You can read our technical decision log to understand why we built it the way we did.

Contributions are welcome. Both SDKs (Node.js and Python) must stay in sync. See our contributor guide and agent instructions for how we work.