# `Urchin`
[🔗](https://github.com/urth-inc/urchin/blob/v0.4.0/lib/urchin.ex#L1)

A Model Context Protocol (MCP) server library implementing the `2025-11-25`
specification over the Streamable HTTP transport.

See `Urchin.Server` for authoring a server (behaviour or DSL) and
`Urchin.Transport.StreamableHTTP` for mounting it as a `Plug`. The convenience
runner below boots a server with a standalone Bandit endpoint.

# `broadcast`

```elixir
@spec broadcast(String.t(), map() | nil) :: non_neg_integer()
```

Sends a notification to every active session on its general (GET) stream.

Useful for fan-out notifications such as `notifications/tools/list_changed` or
`notifications/resources/list_changed`. Sessions without a connected GET stream
buffer the notification for resumption.

Returns the number of sessions notified.

# `protocol_version`

```elixir
@spec protocol_version() :: String.t()
```

The latest protocol revision implemented by this library.

# `start_link`

```elixir
@spec start_link(
  module(),
  keyword()
) :: {:ok, pid()} | {:error, term()}
```

Starts a server module behind a standalone Bandit HTTP endpoint.

Requires the optional `:bandit` dependency. Options are forwarded to
`Urchin.Endpoint.start_link/1`; common ones are `:port`, `:path`, `:ip` and
transport options such as `:allowed_origins`.

## Example

    {:ok, _pid} = Urchin.start_link(MyServer, port: 4000, path: "/mcp")

---

*Consult [api-reference.md](api-reference.md) for complete listing*