Replaces the original 96-line note with a detailed self-contained
brief targeted at someone picking up #42 cold in a new session.
Adds:
- Explicit ruled-out list (wire data, Euler error, stale velocity,
diagnostic instrumentation) — saves rediscovering dead ends.
- The user's "buildings + jumping puzzles" constraint that rules out
blanket sweep-disable.
- Specific file/line targets in PhysicsEngine.cs (470, 478-491,
493-519, 521-530, 532, 534-558) and TransitionTypes.cs (786-846,
1305-1311) with a brief reading order.
- Phase 1 / Phase 2 / Phase 3 investigation plan with concrete
diagnostic harness (`ACDREAM_AIRBORNE_DIAG=1` + `[SWEEP]` log) and
direction-correlation test.
- Per-hypothesis fix paths so the agent doesn't re-derive them from
the diagnosis.
- Full acceptance criteria including build/test gates and visual
test sequence (flat / hillside / running / doorway / puzzle / land).
- Hard rules (don't blame ACE, don't disable sweep, don't touch L.3
motion code, don't reduce sphere dims, etc.).
- cdb breakpoint recipe for retail-vs-acdream A/B comparison.
- Pre-session reading list with line numbers.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>