If a Nebius-backed agent hangs with no output, isolate the model from your client: send a tiny chat completion with a short timeout directly to the API. If that hangs too, the problem is upstream, so switch models and carry on in the same session instead of restarting your tooling. Set aggressive timeouts on first-token waits in production code so one slow model cannot freeze the whole loop.

Context: A Nebius Token Factory cookbook documents a first-token hang that looks like a frozen client. OpenCode waits on the first token, so a model that never sends one looks like a frozen agent. The cookbook recommends testing outside the client with a curl chat completion asking for exactly PONG with a 60-second timeout: a healthy model answers in about a second, while on one documented day a model returned no first token for over 90 seconds while others answered immediately.

## Matched source
Source: Published skill
Original query: "Nebius agent hangs are often one model not sending a first token, test with curl"
Key terms: agent, curl, first, hangs, model, nebius, often, sending, test, token