openai/codex · error · anyhow::Error

MCP client recovery semaphore closed

Error message

MCP client recovery semaphore closed

What it means

Error "MCP client recovery semaphore closed" thrown in openai/codex.

Source

Thrown at codex-rs/rmcp-client/src/rmcp_client.rs:1430

            .is_some_and(|error| {
                matches!(
                    error,
                    StreamableHttpError::Client(
                        StreamableHttpClientAdapterError::SessionExpired404
                    )
                )
            })
    }

    async fn reinitialize_after_session_expiry(
        &self,
        failed_service: &Arc<RunningService<RoleClient, ElicitationClientService>>,
    ) -> Result<()> {
        let _recovery_guard = self
            .session_recovery_lock
            .acquire()
            .await
            .map_err(|_| anyhow!("MCP client recovery semaphore closed"))?;

        {
            let guard = self.state.lock().await;
            match &*guard {
                ClientState::Ready { service, .. } if !Arc::ptr_eq(service, failed_service) => {
                    return Ok(());
                }
                ClientState::Ready { .. } => {}
                ClientState::Connecting { .. } => {
                    return Err(anyhow!("MCP client not initialized"));
                }
                ClientState::Closed => {
                    return Err(anyhow!("MCP client is shut down"));
                }
            }
        }

        let initialize_context = self

View on GitHub (pinned to 339751715c)

When it happens

Trigger: Thrown at codex-rs/rmcp-client/src/rmcp_client.rs:1430 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of openai/codex@339751715c (2026-08-25). Data as JSON: /api/errors/7f6faf6a71aa82b4. Report an issue: GitHub.