Question conversation is marked done after agent stream ends without a terminal event

[ultmaster]

Summary

A Question Node conversation can be displayed with only the user's prompt while the node is marked done. No assistant answer or error is shown, so the empty conversation looks like a storage/read failure.

Observed behavior

For the affected thread:

• space.json persisted the Question Node with status: "done" and viewed: true.
• .history/chat_v2/<threadId>.events.jsonl contained exactly one record: turn_start with the submitted prompt.
• There were no text_delta, done, error, or end events.
• No matching <threadId>.turns.jsonl folded-turn file existed.
• Reopening the Question Node rendered the user bubble but no assistant response or interruption/error status.

The answer is not hidden elsewhere in storage; it was never persisted.

Expected behavior

If an agent SSE stream ends before a terminal event:

• Do not mark the Question Node as successfully completed.
• Surface the conversation as interrupted or errored, ideally with a retry affordance.
• Preserve enough state to distinguish an incomplete persisted turn from a completed empty response.

Suspected cause

Two existing recovery behaviors combine to produce the misleading state:

1. apps/web/src/api/agent.ts treats a terminal-less EOF from streamMessage as successful completion:

   if (!terminal) callbacks.onComplete();

   The reconnect path already treats the same condition as an error (Agent stream ended before a terminal event).

2. apps/web/src/store/canvasStore/load/reconcileQuestionStatus.ts promotes any authored Question Node with a thread ID and non-terminal status to done, without checking whether the persisted conversation has a completed turn.

The Agenetes history materializer correctly identifies the uncovered Tier-1 tail as isIncomplete: true, but the UI history projection currently renders its user request without an interrupted/error status.

These behaviors predate the backend-agnostic storage-read work and are present on upstream/main at 127b820e.

Suggested regression coverage

• A streamMessage response that reaches EOF after turn_start but before done/end/error must call onError, not onComplete.
• Reloading a Question Node whose Chat-V2 log contains only turn_start must not promote it to successful done.
• An incomplete materialized turn should display an interrupted/error state rather than a blank assistant area.

— posted by OpenAI Codex (via the issue-tracker skill)

[matluster]