# MCP server overview

> Aerandil exposes its entire action surface to AI agents over the Model Context Protocol.

Aerandil ships a first-class **Model Context Protocol** server (protocol revision `2025-11-25`, negotiating down to `2025-06-18` for older hosts). It turns the same governed ontology the REST API serves into a surface an AI agent can drive directly — no glue code, no hand-written tool wrappers.

## What it exposes

- **Every registered action is a typed MCP `tool`.** The tool’s input schema is the action’s schema, so an agent gets the same validation the REST API enforces. Apply `apply_rate_recommendation` or `assemble_package_sale` as a tool call.

- **Every tool carries behaviour annotations** — read-only and mutating hints — so a host can gate its confirmation UX before a call ever reaches the engine.

- **Every object type is a `resource`**, addressable with a URI template:

  ```plaintext
  aerandil://object/<type>/<id>
  ```

  An agent can read a `booking` or a `folio` by URI without a bespoke endpoint.

## Transports

The server speaks two transports from one implementation:

- **stdio** — for local hosts that launch the server as a subprocess (editors, desktop agents).
- **streamable HTTP** — for networked hosts, sharing the API’s auth.

The library is host-agnostic; the production host binary reuses the REST API’s engine, store, and auth wiring rather than duplicating it, so the MCP surface and the HTTP surface can never drift apart.

## Authentication

The MCP server authenticates against the same OAuth 2.1 identity as the REST API — an agent is bound by exactly the action scopes its credentials carry. See [Authentication](/guides/authentication/) for how scopes map to actions.

Note

A per-tool reference (every MCP tool, its input schema, and the scope it requires) is generated from the action registry — the same registry that backs the [API reference](/api/). That generated catalogue is being wired in; until then, the API reference is the authoritative list of actions.

---

Source: https://developers.aerandil.com/mcp/overview/