docs(sp4): implementation plan for signal-driven magnitude control
Comprehensive 3-layer implementation plan for the SP4 spec at
docs/superpowers/specs/2026-04-30-sp4-signal-driven-magnitude-control-design.md.
Layer A — additive infrastructure (Tasks A1-A18, no behavior change):
- A1: 40 ISV slot index constants in new sp4_isv_slots.rs module
- A2: wiener_state_buf (141 floats) + clamp_engage_per_block_buf (2048 ints)
- A3: Pearls A+D shared helper (sp4_wiener_ema.rs) + 5 unit tests
- A4: linear-histogram p99 device function (sp4_histogram_p99.cuh) + GPU test
- A5-A9: 5 producer kernels (target_q + atom_pos × 4 branches + param_group_oracle
× 8 groups + grad_norm + h_s2 = 15 fused producers per Pearl B)
- A10-A11: wire 4 captured-graph + 10 cold-path launch sites
- A12: 181 StateResetRegistry entries (40 ISV + 141 Wiener-state float +
2048 Pearl C int)
- A13: retrofit 7 existing pre-SP4 producers with Pearls A+D
- A14-A15: Pearl C engagement counter in 5 Adam kernels + host-side
rate-deficit EMA + force-bump trigger
- A16-A18: 40-test integration validation + L40S regression smoke + audit
doc draft
Layer B — atomic consumer migration (Task B1, ONE coordinated commit):
- Mech 1, 2, 5, 6, 9, 10 consumers flip simultaneously to ISV-driven
- Adam kernels' weight_decay arg from ISV[WD_RATE[group]]
- L1 lambda from ISV[L1_LAMBDA_TRUNK_INDEX]
- HyperParams config fields removed
- Per `feedback_no_partial_refactor`
Layer C — validation + cleanup (Tasks C1-C5):
- C1: retire grad_norm_slow_ema infrastructure (Mech 6 migrated away)
- C2: remove dead Mech 5 fused-kernel parameters
- C3: L40S smoke validation against spec pass criteria
- C4: comprehensive Invariant 7 audit-doc entry
- C5: 5 new pearl memory entries + SP4 close-out project entry
Estimated effort: 3500-4500 LOC across ~25 commits, 1.5-2 weeks of focused
work, 1 L40S smoke validation. Bite-sized TDD tasks with exact file paths,
complete code blocks, and exact build/test commands per task.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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