Distill v2.0.29

Fixes

• Auto effort (/effort auto) now applies Jev's choice on every model call. Before, a split or unsure answer ran the call at the session's pinned effort; with default_reasoning_effort = "max" that was 81% of the calls in a measured session.
• The pick is the cheapest level that holds at least half of Jev's probability mass, so a split answer lands in the middle (medium) instead of on max. The keep_session_effort option and the 0.40 confidence floor are gone.
• Effort levels without a catalog description (Claude models) reach Jev with a standard description of cost and use; catalog descriptions still win.
• Worker subagents with auto effort get the same fix (Sonnet workers used to fall back to high).

Effort changes keep the prompt cache on Claude

• Claude Opus 5.5, Opus 5, Sonnet 5.5, Fable 5.1 and Mythos 5.1 now receive the effort as a per-message marker (Anthropic beta mid-conversation-output-config-2026-07-01) instead of the top-level output_config.effort.
• A top-level effort change used to rewrite the cached conversation; in a measured session the rounds that changed effort were 5.5% of the calls and 23% of the cost. With the marker, an effort switch read 98.6% of the prompt from cache.
• Other models are unchanged.