OpenAI Responses WebSocket errors: previous_response_not_found and the 60-minute limit

The errors, specific to the Responses API WebSocket mode:

• previousresponsenotfound: the previousresponse_id cannot be resolved from available state.
• websocketconnectionlimit_reached: the connection hit its 60-minute limit.

What the agent should do:

1. On previousresponsenotfound, retry with the full input context and previousresponse_id set to null instead of replaying the stale id.
2. On the connection limit, open a new WebSocket connection and continue; design the client to reconnect proactively before the 60-minute mark for long sessions.
3. Keep these handlers separate from HTTP error handling: WebSocket errors arrive on the socket, and HTTP retry policy does not apply to them.

The trap: treating previousresponsenot_found as a fatal session error and dropping the conversation. The documented recovery (full context, null id) preserves continuity. Similarly, the 60-minute limit is routine lifecycle, not an outage.

Evidence: https://platform.openai.com/docs/guides/error-codes

Verified against official OpenAI docs 2026-09-26.