# `ExMCP.Transport.HTTP.LegacySSE`
[🔗](https://github.com/azmaveth/ex_mcp/blob/v1.4.0/lib/ex_mcp/transport/http/legacy_sse.ex#L1)

Client transport for the deprecated MCP 2024-11-05 HTTP+SSE protocol.

This is **not** Streamable HTTP. `transport: :http, use_sse: true` GETs the
same MCP endpoint after `initialize`. This transport instead:

1. GETs `{base}/sse` (or `:sse_path`) with `Accept: text/event-stream`
2. Reads the first `endpoint` event (POST URI + `sessionId`)
3. POSTs JSON-RPC to that advertised URI
4. Receives responses and server requests on the GET SSE stream

## Options

- `:url` - server origin or mount prefix, e.g. `"http://localhost:4000"`
- `:sse_path` - GET path (default `"/sse"`)
- `:post_path` - optional override of the advertised POST path; `sessionId`
  from the `endpoint` event is preserved
- `:headers` - extra HTTP headers
- `:timeout` / `:request_timeout` / `:stream_handshake_timeout`

## Example

    {:ok, client} =
      ExMCP.Client.start_link(
        transport: :sse,
        url: "http://localhost:4000"
      )

# `t`

```elixir
@type t() :: %ExMCP.Transport.HTTP.LegacySSE{
  allowed_private_hosts: [String.t()],
  base_url: String.t(),
  dns_resolver: module() | function(),
  dns_timeout_ms: pos_integer(),
  headers: [{String.t(), String.t()}],
  max_request_bytes: pos_integer(),
  max_response_bytes: pos_integer(),
  max_stream_buffer_bytes: pos_integer(),
  post_url: String.t(),
  session_id: String.t(),
  sse_pid: pid(),
  sse_url: String.t(),
  timeouts: map()
}
```

---

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