[malpern]

Proposes replacing the "choose a keyboard for Caps Lock" requirement with a per-device Caps mapping on every compatible keyboard, and records the spike that tested it on the lab mini.

Doc: docs/architecture/all-keyboards-caps.md

Why

Managed Caps tracks exactly one device (SessionCapsSelection, a one-device lease journal, automaticSelection requiring devices.count == 1). Any Mac with an external keyboard, and every multi-interface board, therefore needs a manual choice. On the lab mini (cl80, X2A, ESP32 fixture) Caps Lock rules have been paused at every session start.

Spike results (mini, master 112c0b1fc)

• A1 ✅ Caps→F18 mapped on all three keyboards in 48 ms; each restores independently. On the fixture a 250 ms Caps hold stops toggling Caps Lock and reaches the worker as F18.
• A3 ✅ A listen-only IOHIDManager attributes raw Caps to its device whether or not that device is mapped, without seizing it. Needs Input Monitoring (KeyPath has it).
• A4 ✅ Merging with an existing pair on another key works and restores byte for byte. For two pairs on the same source key, the first wins.
• A2 ⏸ Hot-plug timing not measured: needs a physical replug. A watcher is ready on the mini.
• A stuck F18 (≈18 s) appeared during the spike under a load average of ~240; likely starvation, not ruled out.

Open questions for review

1. Policy for a keyboard that already remaps Caps Lock (recommendation: leave it alone and report it as uncovered).
2. Confirm multi-interface boards are fully covered.
3. Hot-plug timing and Modifier Keys re-application on arrival.
4. Reproduce the stuck F18 on an idle machine.

Docs only. No code changes.

Review gate: the local Scripts/review-gate.sh could not run (Claude CLI OAuth session expired on this machine, exit 1 "review did not complete"). Relying on GitHub claude-review; do not merge until it passes.

🤖 Generated with Claude Code

[chatgpt-codex-connector]

Codex Review Summary

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Review	Status	Commit	Review trigger
📝 Code Review	🔄 Running since 2026-10-22T05:00:31.246854Z	b8281f9	PR opened

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