model_refusal_no_fallback SDK Event / Claude Code v2.1.193

What

A new system event is now emitted when the model ends a turn with stop reason "refusal" and no fallback model is configured, allowing SDK consumers to handle refusals programmatically.

Details

Event fields: type: "system", subtype: "model_refusal_no_fallback", original_model, request_id, api_refusal_category, api_refusal_explanation, content, uuid, session_id.
A new refused_user_message_uuid field (added to both model_refusal_fallback and model_refusal_no_fallback) contains the UUID of the human turn that triggered the refusal — the rewind target and composer prefill for edit-and-retry.
refused_user_message_uuid is null when the refused turn was not human-authored (e.g., a background task notification or auto-continuation).
Not emitted when a fallback model existed but was declined or gate-failed (that case uses the existing model_refusal_fallback event).

Evidence

New event schema (search for "model_refusal_no_fallback" or "UUID of the user message the refused request was for")

Strings lifted out of the shipped bundle, so the claim above can be checked against them.