The seam (editor-core): a session-local caret — (voice, position, entry
duration), never in the op log, undo leaves it advanced, a deleted voice
clears it — with enter_nominal/enter_pitch/enter_rest funneling to one
insertion core that reuses the pencil's make-room verbatim and advances
only on success. Octave inference is nearest-in-staff-steps to the
preceding note with a downward tie-break — proven unreachable for real
letter pairs (candidate octaves sit an odd 7 steps apart), so the
comparator is tested directly. midi_note_to_pitch (sharps-spelled v1
policy) is the testable core of MIDI entry; x_at_position mirrors
invert_x for the GUI's caret line, extrapolation-tested on non-uniform
anchors after the uniform fixture proved blind to the wrong-segment
mutation.
The GUI (editor-gui): N-toggled entry mode, mutually exclusive with
pencil via a pure toggle_exclusive; mode-gated letters A-G, R for rests,
arrow-key caret movement, the duration palette doing double duty; the
caret drawn full staff height at x_at_position from the staff's own
rendered strokes. G5 locks the entry loop: C-D-E-F entered at the caret,
each advancing position value-asserted as an exact rational before any
pixel, baseline user-reviewed. Twelve mutations killed across the pair,
coordinator re-verified.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The repo's last unverified surface gets a gate. A decoded-RGBA golden
comparator (dimensions first, then raw pixels — never encoded PNG bytes,
proven by a re-encode-invariance test) with three-artifact failure output
and a reviewed-bless mechanism; four golden states over the real Engraver —
as opened, after a scripted pencil insert (target derived through the
session's own inverses, pitch/beat value-asserted exactly), after undo
(asserted equal to the as-opened baseline byte-for-byte, bypassing the
bless path so a broken undo can never bless itself green), and the slurred
casting-off fixture (system count value-asserted). Every state renders
twice and must match itself. Three user-reviewed baselines; rasterize()
split into a pixmap core so the goldens lock the exact surface the GUI
displays; one additive CI step uploads failure artifacts; DECISIONS.md
records the calls, including two engraving gaps locked knowingly (no clef
restatement on later systems; uneven system spacing).
Seven mutations executed and independently re-verified by the coordinator;
full gate green (fmt, clippy 0, workspace 0 failed, docs, conformance 8/8,
requirement counts unchanged).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Levi Neuwirth