Switch notices no longer consume the retry guard or hide the button.
Error, switch model, Retry is the intended recovery path; retry runs on the new model.
New reasoning_delta event; traces persist as a display sidecar stripped from provider feeds.
Sources: compat vendors' reasoning_content and Gemini thought summaries (include_thoughts).
Live-verified on GLM via Together and Gemini 3; Gemini tool loops stay healthy.
Engine appends a display-only notice message on error/interrupted; providers never see it.
New retry frame re-runs a failed turn with no new user message, guarded on the error tail.
GUI renders persisted notices on reload and a Retry button on the trailing error.
GUI flushes the streaming buffer into a durable item on interrupted/error.
Engine persists partial text on the provider-error path like the stop path.
e2e red-green verified; full suites pass.
Stream drops between chunks (+ the pre-first-token wait); pending approvals/questions/plans resolve as interrupted.
Running shell commands die via an executor interrupt hook; skipped tool calls still get results (no orphans).
Also fixes delete_session calling a nonexistent engine.interrupt().
Rohit C Prasad