Documentation of record for the Edmund repo: which doc owns which fact, and how to write in the house style. Load whenever you are writing or updating ANY project doc — docs/ARCHITECTURE.md, CHANGELOG.md, README.md, docs/ROADMAP.md, misc/backlog.md, a docs/<topic>-investigation.md write-up, release docs — or deciding WHERE a newly learned fact, gotcha, bug, or feature idea belongs. Covers the docs-of-record map, the fact-routing decision table, the investigation-doc template, CHANGELOG format (machine-extracted for release notes), commit-message conventions, and doc maintenance duties. Not for making the code change itself, release mechanics, or debugging — see "When NOT to use this skill".
The load-bearing design contract of the Edmund Markdown editor. Load BEFORE any non-trivial code change in this repo; when asking "why is it built this way"; before proposing a new mechanism, subsystem, or refactor; whenever you are tempted to insert/strip display characters, use NSTextAttachment, touch NSTextView.layoutManager, store NSTextBlock/NSTextTable attributes, or add a new overlay/decoration; and before designing anything that syncs storage, selection, undo, or the viewport. Covers the two hard invariants (storage == rawSource; TextKit 2 only), the render pipeline, edit/undo flow, the TextKit 2 drawing model, the read-mode contract, and the known weak points. Not for build/run/release mechanics, debugging triage, or live-repro drivers — see "When NOT to use this skill".
Build, environment, and toolchain runbook for the Edmund repo (native macOS Markdown editor; AppKit + TextKit 2, SwiftPM). Load this skill when: setting up the environment from scratch (fresh clone, new machine, CI mirror); a build fails or a "successful" build behaves stale (change "doesn't take", old code runs, Build complete! but nothing changed); the app crashes on launch or the instant it renders LaTeX; you need to construct the debug bundle (EdmundDbg.app) for live runs; or BEFORE trusting any binary you just built for a visual check or repro run. Covers swift build/test, build-app.sh anatomy (codesign sealing order, SwiftMath bundle placement), the stale-build disease and its detection, safe launch/kill hygiene around the user's live instance, and the CI environment.
Build, environment, and toolchain runbook for the Edmund repo (native macOS Markdown editor; AppKit + TextKit 2, SwiftPM). Load this skill when: setting up the environment from scratch (fresh clone, new machine, CI mirror); a build fails or a "successful" build behaves stale (change "doesn't take", old code runs, Build complete! but nothing changed); the app crashes on launch or the instant it renders LaTeX; you need to construct the debug bundle (EdmundDbg.app) for live runs; or BEFORE trusting any binary you just built for a visual check or repro run. Covers swift build/test, build-app.sh anatomy (codesign sealing order, SwiftMath bundle placement), the stale-build disease and its detection, safe launch/kill hygiene around the user's live instance, and the CI environment.
The executable, decision-gated campaign for Edmund's hardest live problem: the delete-drift class (caret/selection integrity in the live NSTextView / TextKit 2 / input-context layer). Load when the caret or selection lands in the wrong place after a delete/type/IME/drag interaction, when text edits corrupt or desync, when autosave writes stale content, or when logs show ⚠︎LEN-MISMATCH or the "healing storage edit that bypassed didChangeText" breadcrumb. Runs round 7+ at the retiring maintainer's standard: classify, fence off six settled battles, capture evidence, build a deterministic repro, pick from a ranked solution menu with proof obligations, then validate and promote through change control. Not for viewport/scroll drift (that's edmund-debugging-playbook → viewport docs) unless the caret itself moves.
How changes are classified, gated, and reviewed in the Edmund repo. Load at the START of any task that will modify the repo; before committing, branching, or proposing a merge or release; when deciding whether a change needs a test, a screencapture visual check, or a live repro; when unsure what requires explicitly asking the maintainer (push, PR, merge, release, deleting uncommitted work, touching test-files/, adding dependencies). Contains the non-negotiable rules with the historical incident behind each one.
Catalog of every configuration axis in the Edmund Markdown editor — user settings (UserDefaults keys, defaults, where consumed), launch arguments (diagnostic + repro flags), compile-time gates, and logging config. Load when adding or changing a setting, hunting which flag controls a behavior, launching the app with debug flags, auditing defaults, or wiring a new preference into the live editor. This skill drifts fastest of the set — every table ends with a re-verification grep. Not for the invariants (see edmund-architecture-contract), release flags (edmund-release-and-operate), or how to READ the logs (edmund-live-repro-and-diagnostics).
Load this FIRST when any bug report or unexpected behavior arrives in Edmund: caret lands in the wrong place after delete/typing, viewport jumps or scroll-to-target misses, rendering is wrong or missing, empty bands or clipped lines, everything suddenly renders as plain text, app crashes or won't launch, a code change "doesn't take" after rebuild, undo/redo lands the viewport wrong, IME/CJK/accent input misbehaves, right-click shows the wrong menu, window grows on reopen, or a Sparkle update fails. Symptom-to-mechanism triage table, the traps that cost real debugging time, discriminating trace checks, the repro escalation ladder, and the open-bug inventory so known bugs are not rediscovered fresh.