Session handoff — 2026-05-26 mid-day

What this document is: the cold-start snapshot for a fresh Claude Code session. CLAUDE.md gives you the durable architecture + pitfall context; THIS doc gives you the in-progress threads + recent design decisions a new chat would otherwise need to reconstruct by reading git log.

Currency note: updated end of a long 2-day session that shipped v0.5.13 (capture-pipeline reliability sweep + 6-module refactor). Past this date, prefer git log + the GitHub Releases page; supersede this doc whenever its info goes stale.

TL;DR — where the app is right now

• Version: 0.5.13 — published 2026-05-25 evening (release notes: release-notes-0.5.13.md)
• Lint: zero errors, zero warnings (npm run lint)
• Tests: 122/122 passing (npm test)
• CI: GitHub Actions runs lint + tests on every push to main
• Editor type-checking: JSDoc @param/@returns on all 17 pure- module exports; jsconfig.json enables VS Code’s TS-LSP checking
• app.js: ~7,400 lines (down ~700 from session start after the refactor + cleanup); 6 pure-logic modules sit alongside

The 2025-05-25 / 2025-05-26 debug + refactor saga in one paragraph

Daniel hit a long string of “Record-from-JX-3P silent failure” bugs that took most of a day to root-cause. The fixes laddered: a scope error (runningPeak invisible to stopRecording because declared inside startRecording); a latent recordBtn ReferenceError; an onDeviceChange handler that tore down in-flight captures on every spurious Chromium devicechange; a recalibrate flow that reset gain to 1.0× instead of preserving the prior value; a sample-rate- mismatch theory that turned out to be largely wrong (KT USB Audio input is locked at 48 kHz; transfers decode fine through Chromium’s resample anyway). Then a 3-agent Tier 1 audit found a saveLibrary silent-failure data-loss risk + 6 IPC handlers that could throw instead of returning shaped errors + 7 fire-and-forget async sites in the record modal. Then a 4-step (becoming 5) refactor pulled the two biggest modal functions apart into testable pure modules (record-trim, capture-warnings, capture-state, audio-capture, send-timeline + existing calibration-math + library-math), went from 50 tests to 127 to 122 (cleanup), and shipped a global error banner + per-capture telemetry as permanent safety scaffolding. Day capped with ESLint v9 + GitHub Actions CI + JSDoc type annotations — three independent layers of pre-runtime correctness checks. Result: v0.5.13 shipped, codebase meaningfully cleaner, the silent-failure bug class is now detectable at write/lint/CI time instead of “user trips on it and we guess.”

Full bug timeline: read v0.5.13 release notes + the 18 commits between d7f71dd and 444e92b. Don’t try to reconstruct from memory — the commits are detailed and chronological.

Open threads (pickup-ready next moves)

Immediate (~minutes each)

• README screenshots — 4 PNGs to drop into docs/screenshots/. Capture brief at docs/screenshots/README.md. Slots wired in README.md; broken images render until Daniel captures and commits the PNGs. ~5-minute task for Daniel.

• Bruce’s jx3p PR — flagged via spawn_task chip in Daniel’s UI. Docs-only PR to clarify the REST vs TIE wire encoding (CLAUDE.md pitfall #16). Prompt is self-contained: includes the verified test sequence, proposed PR title + body + diff, and a multi-pitch test to run on Daniel’s JX first. Don’t include the local quiet- recording auto-boost patch (pitfall #11) in the same PR.

Higher-leverage, queued (“logical next steps” from chat)

In Daniel’s stated priority order (from a long discussion late 2026-05-25):

1. ✅ ESLint + no-undef — shipped 2026-05-25 (commit 6d4d11d)
2. ✅ GitHub Actions CI — shipped 2026-05-25 (commit 5437f51)
3. ✅ JSDoc type annotations on pure modules — shipped 2026-05-25 (commit b21d493)
4. Apple Developer ID + notarization — $99/yr + ~1 session. Drops the “damaged” Gatekeeper dialog. Biggest user-facing reliability win remaining. Not a code change — DevID setup + signing config in electron-builder + notarization upload.
5. Integration tests for modal flows — JSDOM + tiny harness that asserts “modal opens → button click → next modal appears or error surfaces.” Would have caught today’s silent-failure bug class at test time, not at “Daniel tries the feature and it doesn’t work.” ~3-4 hours.
6. AudioWorklet migration — replace ScriptProcessor (deprecated, Chromium will eventually remove). Lower latency, off-main-thread. Now captured in future-features.md.
7. Library schema versioning + migrations — library.json grew organically (8+ piecemeal fields). Add a version field + a migration list before the next field gets added ad-hoc. ~2 hours. Now captured in future-features.md.
8. More app.js extractions — setupInteraction (~280 lines, untested knob/switch/button wiring), renderPatchList family, shared modal infrastructure. Same pattern as today’s refactors. Now captured in future-features.md.

Deferred

• Step 3e: full capture-lifecycle factory (createCaptureSession with onTick/onAutoStop callbacks) — I deferred this Tuesday night. After Steps 1-4 + 3a/3b/3c/3d, the modal’s lifecycle is already mostly delegated to extracted modules. The remaining inline lifecycle is ~12 lines. The bigger version (factory owns the raf loop, modal subscribes via callbacks) is ~3 hours of meaningful-risk work for modest gain. Worth doing eventually as its own focused session, not at the tail of a long day.

Recent design decisions (verbal calls that don’t show in code)

These came up in conversation and Daniel chose explicitly. Worth preserving so a fresh Claude doesn’t propose to undo them.

• Plain JS only. No TypeScript, no React/Vue/Svelte. JSDoc comments are the type-safety lever (per jsconfig.json).
• Sample-rate warning is advisory, not alarming. Daniel’s KT input is locked at 48 kHz and captures work fine; the original Roland-red “will fail” warning was reframed amber + advisory after empirical testing. Don’t restore the alarmist version.
• TIE cells in the visualizer are Roland blue (not amber). Daniel’s call after the initial implementation. Keeps the visualizer on the brand triad (red/green/blue, nothing else).
• REST encoding label is “rest” not “hold” or “hold or rest” — final wording after the REST vs TIE encoding discovery (CLAUDE.md pitfall #16). The data-level ambiguity exists but “rest” is the dominant single-voice case so it’s the most honest label.
• No Tier 3 (manual smoke test) auto-run. It’s a markdown checklist Daniel runs by hand before each release; CI doesn’t attempt to script Electron flows.
• Stop verbose acknowledgments of pkill SIGTERM notifications. Background-task-exit notifications fire when I reboot Electron via pkill && npm start; the prior chat had me acknowledging each one verbosely, which felt like spam. Going forward: ignore silently unless the exit code is unexpected.

Sequencer-editor design — open questions Daniel hasn’t answered

Came up in conversation, never resolved. Capture so we don’t re-ask:

1. In all-view mode, auto-zoom into a page when entering edit mode, or stay in all-view? Affects how the editor looks at pages 1-8 vs page 0.
2. v1 scope: pitch-only edits, or also add/delete steps + toggle tied? The minimal viable editor is “click note → cycle pitch”; anything more requires per-voice slot handling.
3. Multi-voice handling: edit one voice at a time, or all voices at a step at once? The JX is 6-voice polyphonic so this matters for chord-input flow.

If/when sequencer editor work resumes (parked in future-features.md), surface these to Daniel before designing.

User working style (from cross-session memory)

• First-time OSS author; vibe-coded with Claude Code; values “findings before code on non-trivial tasks”
• Prefers tight, opinionated proposals over open-ended Q&A
• Says “push through” when wanting more decisive execution
• Catches noise/spam from me quickly and tells me to stop — respect that signal immediately
• macOS-only for v1 (Apple Silicon arm64 specifically)

Where today’s work lives

• Code commits: 18 commits between d7f71dd (start of session) and 444e92b (lint cleanup)
• Release notes: docs/release-notes-0.5.13.md
• Smoke test: docs/smoke-test.md
• Screenshots brief: docs/screenshots/README.md
• CLAUDE.md pitfalls new entries this session: #16 (REST/TIE), #17 (Chromium probe cache), #18 (shadow bug class)
• future-features.md new entries this session: AudioWorklet, library schema migrations, integration tests, more app.js extractions, capture-lifecycle factory (3e)

How to use this doc

A fresh Claude reads CLAUDE.md at session start. CLAUDE.md links here. The reading order I’d recommend for a fresh session:

1. CLAUDE.md (architecture + pitfalls) — required
2. This doc (current state + open threads) — required
3. docs/release-notes-0.5.13.md — for the recent-bug context
4. docs/future-features.md — when planning next feature work
5. docs/design-system.md — before touching any UI
6. docs/library-and-midi-spec.md — when working on Library or MIDI
7. docs/record-from-jx.md — when working on the capture flow

Skip the rest until needed.