openai/codex · error · anyhow::Error

timed out handshaking with MCP server after {duration:?}

Error message

timed out handshaking with MCP server after {duration:?}

What it means

Error "timed out handshaking with MCP server after {duration:?}" thrown in openai/codex.

Source

Thrown at codex-rs/rmcp-client/src/streamable_http_retry.rs:99

                .connect_pending_transport(transport, client_service.clone(), attempt_timeout)
                .await
            {
                Ok(result) => return Ok(result),
                Err(error) if should_retry && Self::is_retryable_initialize_error(&error) => {
                    let Some(retry_delay_ms) = retry_delay_ms else {
                        return Err(error);
                    };
                    let delay = Duration::from_millis(retry_delay_ms);
                    warn!(
                        attempt = attempt + 1,
                        max_attempts = STREAMABLE_HTTP_RETRY_DELAYS_MS.len() + 1,
                        delay_ms = delay.as_millis(),
                        error = %error,
                        "streamable HTTP MCP initialize failed with a retryable error; retrying"
                    );
                    if !sleep_with_retry_deadline(delay, retry_deadline).await {
                        let duration = timeout.unwrap_or(delay);
                        return Err(anyhow!(
                            "timed out handshaking with MCP server after {duration:?}"
                        ));
                    }
                }
                Err(error) => return Err(error),
            }
        }

        unreachable!("initialize retry loop should return on success or final error")
    }

    fn is_retryable_initialize_error(error: &anyhow::Error) -> bool {
        error.chain().any(|source| {
            source
                .downcast_ref::<HandshakeError>()
                .is_some_and(|error| Self::is_retryable_client_initialize_error(&error.source))
                || source
                    .downcast_ref::<rmcp::service::ClientInitializeError>()

View on GitHub (pinned to 339751715c)

When it happens

Trigger: Thrown at codex-rs/rmcp-client/src/streamable_http_retry.rs:99 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Timeouts: ETIMEDOUT, deadlines, and hung requests — what actually expires when a request times out.

AI-assisted analysis of openai/codex@339751715c (2026-08-25). Data as JSON: /api/errors/bb1be6074b020d30. Report an issue: GitHub.