mweinbach3/22/2026, 7:43:33 PM

Always dispatch reasoning_delta from item/started (even when initial text is
empty) so the stream key is registered in reasoningItemIdByStream before tool
items can arrive. Guard feed item creation in the reasoning_delta handler so
an empty-text delta registers the key without pushing a blank item to the feed.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Parent1462e40