- distillation runs on opus (env-overridable) with a 4-minute budget
- highlights must name the surface and outcome; vague filler is banned
- tweets target 200-280 chars with concrete changes and varied structure
- betas get their own tester-facing draft carrying `fn update --channel beta`
- prerelease openers read as "Fusion 0.74 beta:" instead of "Fusion 0.74-beta.0"
Claude-author Highlights plus an engagement-oriented tweet (≤280) during changelog distillation, with scheme-free links, Fusion version openers that drop .0 patch, and a soft deterministic fallback when Claude is offline.
Add scripts/lib/distill-release-notes.mjs with:
- distillDeterministic(): groups parsed changesets by category,
renders clean markdown release notes (Keep a Changelog headings)
- buildDistillationPrompt(): builds the context input for AI mode
- DISTILLATION_SYSTEM_PROMPT: system prompt for AI distillation
- Category display order: New → Fixed → Breaking → Security →
Performance → Internal; empty categories omitted
The AI mode (createFnAgent integration) is deferred to U4 where the
engine runtime is available. The deterministic mode is the fallback
contract: it always produces valid output regardless of model access.
14 tests covering category grouping, ordering, empty/edge cases,
prompt building, and legacy entry handling.
