mimo-v2.5-pro streams hang indefinitely — accepts connection, sends keepalives, never produces content

[matteoantoci]

Description

When sending requests to mimo-v2.5-pro via the API proxy, the upstream accepts the connection (200 OK) but never produces any content. SSE keepalive bytes are sent periodically, but no actual data payloads arrive. Streams have been observed hanging for 30+ minutes without timing out or returning an error.

This leaves the client connection stuck indefinitely — the proxy believes the stream is alive (keepalives are flowing) but no content is ever delivered.

Steps to reproduce

1. Send a chat/completions request to mimo-v2.5-pro through the opencode proxy
2. Observe the connection hangs with no content output
3. SSE keepalive bytes continue flowing, keeping the connection alive

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• I just suscribed go , and use in opencode. Try kimi-2.6 and mimo v2.5 pro, no any response still waiting #24552: Reports the same symptom — mimo-v2.5-pro (and kimi-k2.6) returning no response and hanging indefinitely via OpenCode Go subscription
• NVIDIA API models hang indefinitely with "Aborted process" - all models affected (DeepSeek V4, Llama, Mistral, Minimax) #24516: Reports models hanging indefinitely with streaming response handling issues (different provider, but similar root cause pattern)

Please review those issues and consider whether your report is already tracked there.