v4.40.0

Changes since v4.39.0 (2026-09-05).

Added

• Built-in system prompt encourages parallel background tasks via
  StartTask when safe (closes #107).
• Search grounding for Meta muse-spark models (closes #131):
  Responses-only web_search builtin tool plus on_web_search_call /
  on_web_search_done observer events (CLI shows Searching the web...;
  web loop emits web_search / sources events). Citation markers are
  intentionally not rendered: the model's cited sources are low quality.

Added

• Per-model disabled-tools config (closes #144): models with native
  server-side search (Alibaba/Qwen, Meta Muse Spark) hide the external
  WebSearch tool by default; user override per provider/model via
  --set disabled-tools=WebSearch (comma-separated or JSON list).

Fixed

• Corrected ARCHITECTURE.md path in AGENTS.md to dev-docs/ARCHITECTURE.md.
• Privilege badge shows EXEC in red (same as WRITE) instead of yellow.

Changed

• Renamed DeepSeek default model deepseek-v4-flash to deepseek-flash
  with updated per-1M-token rates and refreshed pricing verification date.