memlnaut-nisps/docs/specs/plans/simplification-plan.md

kind	status
plan	active

Simplification Plan 2026-07 — burning down the audit

Dated 2026-07-21. Derived from ../recon/simplification-audit-2026-07.md (finding IDs A*/S*/L*/ST* refer to its inventory; every mitigation here was adversarially verified against the code). Companion: ALIGNMENT.md carries the strategic tier. Proposal only — no phase is adopted until the operator says so; §7 lists the decisions that gate specific items.

§0 Principles and ordering rationale

• Deletion over refactor, refactor over addition. Nothing gets a compat shim without a named consumer.
• Hard constraints hold throughout: nisps/ platform-neutral + allocation-free hot paths; native↔WASM parity ≤1e-5; schema changes ship with both codegen outputs; RT-safe worklet/dual-core comms. Every phase ends with run-all-tests.sh green.
• Docs move in the same commits as code (MAP/ALIGNMENT/spec-corpus sync is part of "done").
• Order: restore verification first — until CI runs, nothing else can be trusted to have landed; then delete dead mass — it shrinks every later diff; then bugs, then truth-consolidation, then the vision builds.
• On adoption of a phase, decompose it into ergo tasks (one per bullet-group below); this doc is the map, not the tracker.

§1 Phase 0 — Restore verification (URGENT, ~half day) — S7, S24, S31, S32; critic gaps 1–3

BURNED DOWN 2026-07-21. All five items landed: memllib feat/nisps-core-swap pushed to monkey-w1n5t0n/memllib and .gitmodules repointed (pin b37fc53 now reachable — data-loss risk closed); the compensating error paragraph in build-firmware-arch.sh deleted; codegen dirty-diff + golden test added to the manifold-tests CI job; a WASM freshness gate (parity harness vs the committed artifact) added to cpp-tests before the rebuild; and the VPS webhook (~/.config/webhooks/meml-deploy.sh, not in this repo) now blocks the deploy unless the CI workflow concluded success on that exact SHA — fail-closed, MEML_SKIP_CI_GATE=1 to override.

CI has been 100% red on main since 2026-07-13; the cause and the data-loss risk are the same object.

1. Push feat/nisps-core-swap to the monkey-w1n5t0n/memllib fork (3 commits incl. pin b37fc53 currently existing only on this disk); repoint .gitmodules to the fork URL; verify a fresh clone + submodules: recursive checkout succeeds; delete the compensating error-message paragraph in scripts/build-firmware-arch.sh (S7).
2. Confirm CI goes green end-to-end; only then trust any subsequent gate claims.
3. Codegen enforcement in CI (S24, S31): in the manifold-tests job (bun already present) run both generators + the golden test and fail on dirty diff — makes the "regenerated outputs in the same change" rule real.
4. WASM freshness gate (S32): before CI's own WASM build overwrites it, run the existing parity harness against the committed manifold/public/nisps.{js,wasm} so a stale committed artifact fails loudly. (The same artifact is what the VPS webhook ships to production.)
5. Deploy gating (critic gap 3, operator decision §7.4): today push-to-main deploys to meml.lnfinitemonkeys.org/next/ with no gate at all. Cheapest real fix is VPS-side (webhook checks the commit's CI status before building); repo-side minimum is documenting the risk in manifold/ONBOARDING.md.

§2 Phase 1 — Dead-mass deletion sweep (~2–3 days, one commit per group)

All verifier-checked deletions; protected exceptions noted. Rough net effect: thousands of lines removed with zero live-behaviour change.

• Repo root / hygiene: retired-playground dist + root Playwright rig + root package.json/lockfile/node_modules (S23, S29, L55); NISPS_CORE_EXTRACTION_PLAN.md + NISPS_CORE_TASKS.md (L48/L36); data/ (L36); committed .claude/worktrees/ fragment (L32); prune stale worktree-* branches.
• nisps core/ml: fixed_buffer.hpp + its test (L27); dislike_multiplier_ (L26); copy_weights_to(span) to drop flat_ from FixedStorage and the per-gesture double copy (L28); perf-macro regime — delete the 3/5 dead SRAM macros, fix the one misshapen NISPS_AUDIO_FUNC use in midi_io.hpp (S21, L13, closes old ALIGNMENT #4). The 16 KB loss-history buffer (L25) waits on the telemetry decision (§7.3).
• engines/modes: voice_space.hpp (L3); no-op VoiceSpace boilerplate on the five engines without real voice spaces (L9); SawOsc/SquareOsc — keep SineOsc, the selftest uses it (L4); input_dirty_ (L5); VerbFX dead fields/setters (L6); MEMLCelium inert feedback path after checking the upstream app for a missing write (L7). DriverConfig (S4) waits on §7.2.
• wasm bridge: dead C-API entries through the full 5-layer chain — keep EXPORTED_RUNTIME cwrap/heaps (parity + wasm-load tests build their API via Module.cwrap) (S33); publishWeights_ 200 Hz weight-copy channel (S34); worklet loader dead scaffolding + throwing import stubs (L54).
• manifold UI: dead focus/altitude system — SplitStage, ReadoutStrip, InputMini, AltitudeNav, CompactAxis, keep MiniMeters and don't touch engine.feedback.setFocus (S15); decorative controls — A/B, fake seed/gradient, snapshots, master volume, bpm, training-param sliders per verifier notes (S16, absorbs L1's delete-half); BackendAdvanced.tsx duplicate editor table (S18); ConsoleCtx prune to consumed fields (S19); 5 dead primitives (L22); dual backend catalogues (L23); inert soloMode selector + FeedbackController vestiges (L20, L21).
• backends: dead protocol legs — sendState/sendWeights, legacy array format, unreceivable /nisps/state, unused module-output listeners (L16); delete bridge.mjs, keep bridge.ts + compiled binaries as distribution (S11).
• vcv: vcv/test/ + Makefile.dist + tracked ELF (L33).
• firmware: daisysp — 41 dead .cpp per build, delete vendored tree + symlink, fix docs that call it a submodule (S8); input_router.hpp zero-logic layer (ST2); peripherals dead declarations + extracted commit_and_train helper (L14).

§3 Phase 2 — Behaviour bugs (~2 days)

BURNED DOWN 2026-07-21. All nine landed with regression tests where testable. Two deviations from the text below, both deliberate: L35 was resolved by DELETING the OSC full-state bridge rather than moving its JSON to the worker — reading the current transport showed both directions have zero consumers (manifold's osc-client.ts never sends /nisps/state|/nisps/weights and bridge.ts drops them), so relocating heap-heavy work to serve nobody was the wrong shape; dataToJson/dataFromJson are untouched and still serve Rack patch save/load off the audio thread. S35 required extending nisps_ml_describe from a 6-int to a 7-int wire format, which forced matching buffer-size fixes in two call sites outside the finding's scope (wasm-worker.ts, parity_wasm.mjs) that would otherwise have overflowed the WASM heap by 4 bytes on every call. Also fixed en route: manifold/package.json's test script listed test files explicitly, so new unit tests were silently not run — now a glob.

• S35 Dual example store: name kDefaultMaxExamples = 128 once in nisps, expose via nisps_ml_describe, align the TS mirror (currently 100) — fixes train()/trainAsync() diverging past 100 examples and the latent OOB sample-weight read.
• S10 VCV bridged mode truncates inputs to 2-D: EngineApi.inputVector() returns the spine's full N-dim raw vector; VcvBackend tracks/dead-zones the full length.
• L34/L35 VCV plugin RT-safety: worker deep-copies example vectors into staging before flagging; move full-state JSON off Rack's audio thread onto the existing worker (reuse the staged-weights pattern).
• L18 MIDI input flooding React per CC message → notify only on binding-list changes; L19 BackendManager dropping a switch requested mid-switch; L24 ConsoleApp global-listener effects re-subscribing every render.
• S30 lint-cpp: cover nisps/pipeline/ + core/, strip comments before matching, extend the heap pattern set — the no-heap gate currently has proven false-negative modes; L52 parity-check.sh unreachable FAIL branch under set -e.
• L51 parity runner header/stage-list drift (4-stage/v1 documented vs 7-stage/v5 real).

§4 Phase 3 — Single-source-of-truth consolidation (~2–3 days)

BURNED DOWN 2026-07-21, except S26, which is now an operator decision backed by a per-field inventory (see below). Every generated numeric value is byte-identical to what was committed — the diff on the generated dirs is purely additive, which is what a relocation of truth should look like. Three audit claims were wrong and are corrected in the commits: L8's "breakor and elysiamorf duplicate ratio_seq" (elysiamorf has no ratio_seq at all; the real duplicate pair is breakor + memlcelium), ST13's proposed destination would have broken codegen (the generator ajv-validates every *.json directly under schemas/midi_devices/, so the provenance file went to a sources/ subdir), and ST4's remaining-copy count.

S26 — decision now cheap. ml.default_spread is already wired on both targets (the audit's "zero consumers" claim was a quarter wrong). ml.default_learning_rate and ml.default_max_iterations are unread on both targets, but every schema carries exactly 1.0/1000, which are precisely the values hardcoded in mlp.hpp and wasm-iml.ts — so wiring them is numerically a no-op today and simply makes the schema the source of truth it claims to be. ml.input_channels is read by nobody at runtime but is validated at codegen time and carries real information for sound_analysis_midi. Per-param curve is a trap: params_notes.md says it is DESCRIPTIVE — it documents that engine voice spaces already square the value internally — so "wiring" it would double-apply squaring on 35 params.

• S1 Mode identity: codegen emits an ALL_MODE_SCHEMAS registry; SCHEMA_MODES becomes a mode_id→display-overlay map (labels/glyphs stay legitimately hand-curated); L37 delete the hand-switched modeEngineId (route on schema engine_id, single named exception for sound_analysis_midi).
• S5 codegen emits per-mode kXSchema ParamSchema constants (deletes 9 hand-written 12-field blocks); S6/S25 MLP template args come from generated constexpr dims (or static_assert parity), killing the hand-typed-dims dual truth; L11 ext-synth ML config folds into the same pipeline.
• S26 Schema surface honesty: per-field wire-or-delete pass (default_learning_rate/max_iterations both-platforms-or-neither; input_channels; per-param curves) per the verifier's corrected list.
• L38 one TS applyCurve (mapping.ts's spec-anchored formula survives); ST4 one GROUP_COLOR source; L8 extract shared ratio_seq/SeqClock/EventQueue for the sequencer engines; L17 BaseBackend mirroring BaseSource for status/throttle plumbing; ST12 shared codegen lib.ts; L39 delete the clobbering seed script (git keeps it); ST13 move synth-midi-cc.json under schemas/midi_devices/.

§5 Phase 4 — PlatformIO migration (vision 4) (~2–3 days) — A6, S2, L12, S9

One cut, no dual path. firmware/useq-celium/ already proves the PIO + arduino-pico pattern in-repo.

• platformio.ini with one [env] per firmware variant passing -DMEMLNAUT_MODE_TYPE=<alias>; selftest becomes a plain -DNISPS_SELFTEST=1 env. Deletes: the sed/python machinery in firmware-common.sh that mutates the committed .ino, the .ino comment-registry, the entire NISPS_ST_* token-paste table (already silently missing the currently-active SLPWorkshop variant — L12), the sketch-tree symlink forest, and the global TFT_eSPI library mutation (handled via PIO lib config/build flags instead).
• memllib consumption decision (§7.5): SETTLED — the submodule bump landed; the vendoring copy is what remains. See ../recon/memllib-usage-inventory.md. Result: all 24 compiled TUs link, so the vendoring surface is ~1.8 MB / 84 files — all of memllib bar examples/; there is no small subset to lift. The operator chose "rebase then vendor", but on inspection there was no rebase to do: all three fork commits touch only examples/, which is not in the sketch symlink forest and is never compiled, and whose content is already ported into nisps/ml/. So the fork is dissolved and the submodule is repointed at upstream, pinned to current main — verified by building all three variants (+316 bytes flash, one constexpr→const fix in the .ino because upstream made kSampleRate runtime-settable). That bump brings the l r input swap hardware fix and the NavigateToView the SelfTest variant had already been written against. Vendor from this snapshot, recording the upstream commit so a re-sync stays a documented diff.
• Then S9: a CI job compiling 2–3 representative envs with cached toolchain — firmware enters an automated gate for the first time.

§6 Phase 5 — Vision-facing architecture (each item spec-first, own session)

• 5a Mode-layer reunification (A1, A5). The verified shape: do not bind monolithic mode objects into WASM and do not delete the per-primitive C API (contradicts the locked P2/P3 architecture and the two-instance RT split). Instead storage-policy the ModeBase orchestration the way P2 did MLPCore, so control-tick behaviour (jolt stepping, OU, routing, event pump) exists once in C++ and the browser stops hand-mirroring it. Needs its own spec before code.
• 5b Browser mode coverage honesty (A2). Add an audio-topology notion (generator / audio-in-fx / event-only / analysis) so Manifold stops cataloguing 4 modes that structurally cannot run; wire mic input for the audio-in class (absorbs old ALIGNMENT #1); event-only modes need transport/MIDI-out UI, or explicit "hardware-only" labelling.
• 5c Curated/advanced split (A3, A7). Product model first (§7.6): what is a "curated preset" — schema + backend preset + input map + trained net? Then: instrument picker rendered from the already-plumbed ctx.modes/setModeId (engine reshape-on-switch already works); per-drawer depth levels as the disclosure mechanism rather than one global boolean; backends/presets.ts + schemas seed the data model (add the missing cv backend to presets — small bug from A3's verification).
• 5d Hardware editor (A4, S14). The repo already contains the right discipline: useq-celium's C-header wire-protocol truth + TS mirror + parity test. Apply it to a MEMLNaut USB-serial protocol; give firmware an actual command surface + on-device persistence; settings/training payloads derive from schema codegen, not hand-defined tables. InputChain/OutputChain firmware wiring (L29) lands here or gets its comment softened now.
• 5e Training-health telemetry — one decision, four fragments (critic gap 5; §7.3). Either it's a feature (wire the already-plumbed get_layer_stats + a loss-history ABI to the advanced mode, delete the fakes) or it isn't (delete the 16 KB buffer L25, the fabricated gradient UI L1, and old ALIGNMENT #2). Decide once; stop maintaining all four limbs.
• 5f Performance measurement (critic gap 4). A host-side blocks-per-second benchmark for engine_process_block (native + WASM), and build-firmware.sh emitting a per-variant flash/RAM size report — makes the headline constraint enforceable instead of vibes.

§7 Operator decisions needed

1. S20 legacy feedback modes (RandomiseOutputs/RandomiseMlp/Diffuse/on_drag): deletion reverses the explicit "keep for A/B comparison" in docs/adr/rl-feedback-design.md — delete (and amend the ADR) or keep?
2. S4 DriverConfig: wire the firmware audio driver to read it at mode start (makes mic/line settings real) or delete the contract from the concept + all 8 engines. No dead middle.
3. Telemetry (§6.5e): feature or delete.
4. Deploy gating (§1.5): gate the webhook on CI, or accept ungated deploys knowingly.
5. memllib ownership (§5): fork-pin vs vendored subset vs upstreaming to MusicallyEmbodiedML.
6. Curated-preset product model (§6.5c): what a preset bundles; where curation lives.
7. S12 inputs composition: mix-and-match multi-source remains an unreversed 2026-06-28 decision with groundwork deliberately laid — schedule the UI, or keep dormant (spec relabelled either way).

§8 Docs/specs disposition (executes alongside phases; ~1 day)

Doc	Disposition
aimmersive-clone-spec.md	Archive (_archive/, deprecated-by note) — specs a retired product; strip chat residue (L42)
feedback-modes-port-spec.md	Reclassify kind: plan, status: executed; ADR + feedback.hpp are the truth (L43)
plans/BUILD-PLAN.md	status: executed; two-line survivors note (L44)
plans/playground-2.0-rewrite-plan.md	status: superseded (retired target) (S3)
engine-architecture.md	Excise dead playground2 sections; keep EngineApi-seam + spine contract with supersession header (S3, L45)
MAIN.md	Fix the ≥6 contradicted claims; update registry rows (S27)
manifold-parity-features-spec.md	Reclassify plan; mark Jolt/OU executed-by-other-means; presets/pins sections stay live feeding 5c (S28)
vcv-module.md + vcv/README.md + NISPS-FORMAT.md	Prune to the current 8→16 contract; one format spec, not two (S22, L46)
inputs/backends/dock spec trio	Mark grounding sections historical; fix dead cites; drop aimmersive counterpart links (L50)
MAP.md	Flatly-false lines fixed with this commit (phantom MEMLCelium-upstream, exploration.ts, daisysp "submodule", pre-P5 sentence, perf-attr "globally" claim); the rest moves with the phases that change the code (L2, L15/L31/L41, L49, ST7, ST15)
AGENT-REFERENCE.md	Pre-P5 sentences updated (L49)
codegen/README.md	Rewrite or shrink to a MAP pointer; drop port-solidjs CI trigger (ST10)
Root NISPS_CORE_* relics	Deleted in Phase 1 (L48)
ALIGNMENT.md	Rewritten with this commit (L30, L47, ST6 fold into their code phases)

§9 Effort summary

Phase	Cost	Depends on
0 Restore verification	~half day	— (do first, includes the only data-loss risk)
1 Dead-mass deletion	2–3 days	0 (green gates to delete against)
2 Behaviour bugs	~2 days	0; independent of 1
3 Truth consolidation	2–3 days	1 (less mass to consolidate)
4 PlatformIO	2–3 days	0.1 (memllib remote); §7.5
5 Vision builds	spec-first, weeks, incremental	1–4 recommended; §7 decisions
Docs disposition	~1 day	interleaved

Phases 1–3 are safe, mostly-mechanical, and could be largely agent-driven with the existing gates. Phase 4 is bounded and proven in-repo. Phase 5 is where the product decisions live — each item deserves its own spec + session, in the order 5c → 5a → 5d (curation is the user-visible payoff; reunification derisks everything mode-shaped; the editor closes the hardware loop).