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+# Repository Conventions
+
+Conventions for human contributors and AI agents working on this repository.
+
+## Style
+
+- Terse technical prose. No emojis in commits, issues, PR comments, or code.
+- TypeScript strict mode. No `any`, no `unknown` casts where avoidable, no `@ts-ignore`, no `@ts-expect-error`, no enums.
+- ESM modules with `.js` suffix in runtime import paths.
+- Tabs for indentation. Double quotes for strings.
+- Tests use vitest with `#given .. #when .. #then` descriptions or plain `// given / // when / // then` body comments.
+
+## Commands
+
+- `npm install` - install dependencies.
+- `npm test` - run vitest once.
+- `npm run typecheck` - strict TypeScript check.
+- `npm run check` - type check, biome, and build.
+- `npm pack --dry-run` - release package smoke test.
+- `node dist/cli.js hook post-tool-use < fixture.json` - smoke-test the Codex hook.
+
+## Constraints
+
+- No Bun APIs. Runtime is Node only because Codex launches plugin hooks with Node.
+- Keep Codex `PostToolUse` hook behavior covered by tests.
+- Keep `apply_patch` extraction covered by tests.
+- `apply_patch` must support Codex `tool_input.command`, raw patch text, and OMO-compatible metadata.
+- Hook output must use the stable Codex hook JSON contract.
+- Do not expose an MCP server or MCP tool from this plugin.
+
+## Don'ts
+
+- No `git add -A` or `git add .`. Stage only the files you changed.
+- No `git commit --no-verify`. No force pushes. No history rewriting on shared branches.
+- Do not couple this package back to pi, omo, or senpi internal source paths.