Cursor rule

1---
2description: Scope a change and land it without a multi-round review loop
3globs: **/*
4alwaysApply: true
5---
6 
7# Change discipline
8 
9The canonical text is **`AGENTS.md` → "Change discipline"**, and the "Definition
10of Done" section beside it. This file exists only because Cursor reads
11`.cursor/rules` and not `AGENTS.md` — Claude Code reads AGENTS.md via
12`CLAUDE.md`, and it is Codex's source of truth. Keep the two in sync; if they
13disagree, AGENTS.md wins.
14 
15The short form:
16 
171. **Acceptance criteria in the PR before the first commit**, plus an explicit
18   statement of what the change does NOT cover. Skipping this is what turned
19   PR #97 into twelve review rounds: with no written finish line every round
20   ended at "I fixed what was reported" and the next round moved it, and with no
21   stated boundary, findings equally true of `main` arrived as blockers.
222. **Put a shared rule where every path reaches it, then delete the other copy** —
23   not at the site the report happened to mention.
243. **Grep for siblings before calling a class closed.** Every single-instance fix
25   in #97 had two or three.
264. **Make a test fail before trusting it, and pin the CALL, not just the
27   function.** Delete the call site and confirm red.
285. **Never assert wall-clock time.** Assert the observable consequence instead.
296. **Run the gates and READ the output** — build, typecheck, test, lint, the three
30   CI smokes, `release:qa` — then wait for CI on the SHA you actually pushed.
31