**A1 is an exhaustive loop over all 35 function keys, not spot checks.**
The defect it closes was `_ => return None` swallowing F13 upward, and a
test covering F1-F12 would have passed against exactly that. Each row
also asserts `should_forward_key`, because translating without
forwarding leaves a key mapped and inert --- which reads as a daemon
keymap gap rather than a frontend one.
**A2 asserts both halves**: `BackTab`, and `Shift` still set. A
`BackTab` that lost its modifier is indistinguishable from one the user
did not shift. **A3** likewise pairs the mapping with forwarding.
**A4 establishes idle rather than asserting it.** A fresh `State` starts
with `dispatch_idle` false --- the daemon has not spoken yet --- so the
first version of the row asserted the precondition and failed. Had it
been written the other way round it would have tested the INTERCEPTING
case under an idle name, which is the state where Escape never quit
anyway: the row would have passed while proving nothing about the
behaviour A4 changes. It now sets idle, confirms nothing intercepts, and
asserts both halves: the Escape reaches the daemon AND no exit occurs.
**The frozen-byte pin sits on `PanelPointer`, not on `TextInput`, and
the placement is the point.** `TextInput` is appended, so its own
round-trip is byte-identical whether or not a variant was inserted
beneath it; only the PREVIOUS final variant's bytes move. Every v6-v23
daemon decodes the variants below `PanelPointer` on every session, so an
insertion anywhere earlier is a silent wire break for all of them.
MY FIRST MUTATION OF THAT PIN WAS WRONG AND THE PIN WAS RIGHT. I
inserted the wedge variant before `TextInput` --- which is to say AFTER
`PanelPointer`, exactly where an append belongs --- and the pin passed,
correctly, because nothing shifted. Re-run with the wedge BEFORE
`PanelPointer`, it fails with the discriminant visibly moving 15 -> 16.
Worth recording because a mutation that targets the wrong side of the
boundary reports the pin as vacuous when it is sound.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016bqGA6s9tTUFzYpbeW3tai