MCP doesn't work with agda-mcp

What version of Codex is running?

50.0

What subscription do you have?

API

Which model were you using?

_No response_

What platform is your computer?

darwin arm

What issue are you seeing?

Codex cli does not initialize with agda-mcp where claude code does.

https://github.com/faezs/agda-mcp

Starting Agda MCP Server on http://localhost:3000/mcp
Session isolation enabled: pass 'sessionId' parameter for multi-agent support
Persistent REPL started
Starting persistent Agda REPL thread...
SessionManager: Created with SessionConfig {sessionTimeout = 600, gcInterval = 60, maxSessions = Nothing}
Starting MCP HTTP server on localhost:3000/mcp
Client version: 2025-06-18, using: 2025-06-18
Received initialized notification - server is ready for operation

■ MCP client for `agda` failed to start: handshaking with MCP server failed: Send message error Transport
[rmcp::transport::worker::WorkerTransport<rmcp::transport::streamable_http_client::StreamableHttpClientWorker<reqwest::async_impl::client::Client>>] error: Transport channel closed, when send initialized notification

What steps can reproduce the bug?

% agda-mcp in one terminal, codex in another with:

```config.toml

Make model/provider explicit so the right provider block is used

model = "gpt-5-codex"
model_provider = "openai"
model_reasoning_effort = "high"
request_max_retries = 40
stream_max_retries = 100
stream_idle_timeout_ms = 300000
wire_api = "responses"

[mcp_servers.agda]
transport = "http"
url = "http://localhost:3000/mcp"
experimental_use_rmcp_client = true

### What is the expected behavior?

_No response_

### Additional information

_No response_