Build sync mechanism for .github/instructions/globals.instructions.md (4k-cap follow-up)

[jamditis]

Three repos now have `.github/copilot-instructions.md` files at the 4k-char silent-truncation cap:

• `rosen-frontend` — 3995 chars
• `class` — 3993 chars
• `houseofjawn-bot` — 3992 chars

Each is one byte from invisibly losing content the next time a bug class is added. The cause: 1700 chars of Joe's user-level globals (sentence-case, anti-slop, AI-attribution, banned words, favicon/OG scoping) restated in each project's `copilot-instructions.md` because Copilot's PR review bot does NOT read `/.claude/CLAUDE.md`.

Long-term fix

Per GitHub's 2025-11-12 changelog, `.github/instructions/*.instructions.md` files are also read by Copilot's PR review bot, with `applyTo` glob scoping and an `excludeAgent` opt-out. A path-scoped `globals.instructions.md` would let projects centralize the globals block once and shrink each `copilot-instructions.md` back to project-specific bug classes.

Mechanism options

1. Sync script in `tools/` — reads `~/.claude/CLAUDE.md`, writes `.github/instructions/globals.instructions.md` to each subscribed repo. Run via cron, pre-commit hook, or manual `tools/sync-globals.sh `.
2. Submodule — point each repo at a shared `copilot-globals` repo. Cleaner long-term, more friction per-repo.
3. Manual + git-tracked — single canonical `globals.instructions.md` copied on repo creation, updated by hand when globals change.

Scope of this issue

• Pick a mechanism
• Build it
• Migrate the three over-cap files (rosen-frontend, class, houseofjawn-bot) to use it
• Document the workflow in `tools/CLAUDE.md`

Other repos adopt opportunistically (probably worth doing on socialsnag, claude-skills-journalism, reroute-nj, tools too).

Reference: MEMORY.md → `reference_copilot_pr_review_reading_scope.md` for the underlying constraint.

[jamditis]

Architectural pivot — this issue is largely OBE

Joe pointed out 2026-05-02 that Copilot's PR review bot is a bug finder, not a style linter — it won't flag English-prose conventions like sentence case or banned-words use anyway. So the ~1700 chars of restated globals taking up 4k-cap budget in each repo were largely wasted enforcement-wise.

The right architecture isn't "sync globals into more places" — it's "stop putting non-bot-enforceable rules in copilot-instructions.md at all."

Revised plan

1. Drop sentence-case, banned-words, and broad style rules from each repo's .github/copilot-instructions.md. Those don't get enforced by the bot.
2. Keep narrow, bot-enforceable rules: AI-attribution trailers in commits/PR bodies, favicon <link> + OG meta tags in public-facing HTML, "no innerHTML"-type code patterns.
3. Each repo's .github/copilot-instructions.md shrinks back to project-specific bug classes (where it's most useful anyway).
4. English-prose rules stay enforced via:
   • ~/.claude/CLAUDE.md (Claude's own behavior)
   • CI hooks / pre-commit for hard cases (banned words, emoji-in-code)
   • stop-and-check.py for editorial copy

Status

This issue stays open as the tracking ticket for the cleanup sweep. The work is now: open one PR per repo to slim the .github/copilot-instructions.md files (vs. the original "build a sync mechanism").

Memory updated: feedback_copilot_review_is_bug_finder_not_style_linter.md.