docs(01-02): complete end-to-end verification plan with tuning findings

.planning/STATE.md

@@ -10,11 +10,11 @@ See: .planning/PROJECT.md (updated 2026-04-11)
 ## Current Position
 
 Phase: 1 of 4 (Core Pipeline)
-Plan: 1 of 3 in current phase
+Plan: 2 of 2 in current phase
-Status: Executing
+Status: Phase complete — awaiting verification
-Last activity: 2026-04-11 -- Completed 01-01-PLAN.md
+Last activity: 2026-04-11 -- Completed 01-02-PLAN.md
 
-Progress: [#.........] 10%
+Progress: [##........] 20%
 
 ## Performance Metrics
 
@@ -27,7 +27,7 @@ Progress: [#.........] 10%
 
 | Phase | Plans | Total | Avg/Plan |
 |-------|-------|-------|----------|
-| 01-core-pipeline | 01-01 | 2min | 2min |
+| 01-core-pipeline | 01-01, 01-02 | 27min | 13.5min |
 
 **Recent Trend:**
 - Last 5 plans: -
@@ -48,6 +48,10 @@ Recent decisions affecting current work:
 - [01-01]: Default audio_cover_strength=0.9 for high melody fidelity
 - [01-01]: Conservative -60 dBFS silence threshold with warning (not hard fail)
 - [01-01]: Temp directory isolation for ACE-Step UUID output before renaming
+- [01-02]: audio_cover_strength=0.3 is optimal (0.9 garbled, 0.5+ copies source)
+- [01-02]: cover_noise_strength must be 0.0 (any >0 produces source copies)
+- [01-02]: Seed variance dominates quality — multi-take cherry-pick workflow required
+- [01-02]: Simple instrument captions outperform verbose descriptive captions
 
 ### Pending Todos
 
@@ -60,5 +64,5 @@ None yet.
 ## Session Continuity
 
 Last session: 2026-04-11
-Stopped at: Completed 01-01-PLAN.md
+Stopped at: Completed 01-02-PLAN.md — all plans in phase 01 done, awaiting verification
 Resume file: None

.planning/phases/01-core-pipeline/01-02-SUMMARY.md

@@ -0,0 +1,83 @@
+---
+phase: 01-core-pipeline
+plan: 02
+subsystem: pipeline
+tags: [ace-step, cover-mode, tuning, seed-control, quality-testing]
+
+requires:
+  - phase: 01-01
+    provides: "hum2inst.py CLI script"
+provides:
+  - "Validated end-to-end pipeline with real humming input"
+  - "Tuned generation parameters (strength=0.3 optimal)"
+  - "Multi-take seed generation workflow"
+  - "JSON run logging for reproducibility"
+affects: [02-quality-presets]
+
+tech-stack:
+  added: []
+  patterns: [multi-take-generation, json-sidecar-logging, seed-reproducibility]
+
+key-files:
+  created: []
+  modified: [hum2inst.py]
+
+key-decisions:
+  - "audio_cover_strength=0.3 is optimal default (0.9 garbled, 0.5+ often copies source)"
+  - "cover_noise_strength=0.0 required (any >0 produces near-identical source copy)"
+  - "Seed variance dominates output quality — multi-take cherry-pick workflow is necessary"
+  - "Custom verbose captions hurt quality — simple instrument captions work best"
+  - "JSON sidecar logging for every output WAV to track parameters"
+  - "Seed embedded in filename for traceability"
+
+patterns-established:
+  - "Generate N takes with --takes, cherry-pick best by ear, reproduce with --seed"
+  - "JSON sidecar per output with full parameter snapshot"
+  - "Parameter sweep methodology: isolate one variable, same seed, compare"
+
+requirements-completed: [MEL-01, MEL-02, MEL-04, INST-01, INP-01, OUT-02, PIPE-01]
+
+## Self-Check: PARTIAL
+
+quality-notes: |
+  Pipeline runs end-to-end without errors. Best outputs follow melody contour and
+  sound recognizably like target instrument. Quality is seed-dependent — some seeds
+  produce excellent results, others garbled or off-topic. Strength=0.3 with default
+  params is the confirmed sweet spot. This is a model capability ceiling, not a
+  script issue.
+
+duration: 25min
+completed: 2026-04-11
+---
+
+# Phase 1 Plan 02: End-to-End Pipeline Verification
+
+**Validated pipeline with real humming input, tuned parameters through systematic testing, added seed control and run logging**
+
+## Performance
+
+- **Duration:** ~25 min (includes iterative tuning with user)
+- **Tasks:** 2/2 (Task 2 checkpoint resolved through iterative testing)
+- **Files modified:** 1
+
+## Accomplishments
+- Pipeline ran successfully on first attempt with no code fixes needed
+- Systematic parameter sweep across strength, noise-strength, guidance, steps, shift, sampler, vel-clamp, vel-ema
+- Identified optimal defaults: strength=0.3, noise-strength=0.0, guidance=5.0, steps=50
+- Added seed control (--seed), multi-take generation (--takes), caption override (--caption)
+- Added 6 advanced tuning flags (--guidance, --steps, --shift, --sampler, --vel-clamp, --vel-ema)
+- Every output now has JSON sidecar with full parameter log
+- Seed embedded in output filename for traceability
+
+## Key Findings
+- **audio_cover_strength** has a narrow sweet spot around 0.3 — above 0.5 often copies source, at 0.9 produces garbled "deep dream" output
+- **cover_noise_strength** is cliff-like — any value > 0 produces near-identical source copies
+- **Seed variance dominates** — same parameters produce wildly different results across seeds
+- **guidance=7.0** improved melody fidelity but shifted timbre too bright (glockenspiel-like)
+- **heun sampler** produced most authentic piano sound but melody diverged
+- **Custom verbose captions** (descriptive register/tone) degraded output severely
+- **Higher steps (100)** and **shift values** did not improve quality
+
+## Task Commits
+
+- `45f6863` feat(01-02): add generation tuning params, seed control, multi-take, and run logging