# Tasks: enterprise-server-health-check

**Change ID**: enterprise-server-health-check
**Package**: `@suaveplan/health-check`
**Target path**: `server/infra/health-check`
**Prerequisites on Verdaccio**: `@suaveplan/error`, `@suaveplan/types`, `@suaveplan/logger`

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## 0. Pre-flight (non-negotiable)

- [ ] 0.1 Confirm clean working tree (`git status` reports nothing) and no in-flight worktrees with uncommitted work (`git worktree list` then `git status` in each)
- [ ] 0.2 If any worktrees exist under `.claude/worktrees/`, account for each one: still-active agent, work-pending-merge, or stale-and-prune. Stale worktrees MUST be removed (`git worktree remove`) before opening a new one — code that has been lost twice on main is the failure mode this guards against.
- [ ] 0.3 Confirm the package set in `MANIFEST.md` matches `find packages -maxdepth 3 -name package.json` count. Drift here means a prior change archived without regenerating the manifest.

## 1. Scaffold

- [ ] Create directory tree per `proposal.md`.
- [ ] `package.json` at `0.1.0`, `"sideEffects": false`, exports `"."` + `registry` + `server` subpaths.
- [ ] Deps: `@suaveplan/error workspace:^`, `@suaveplan/types workspace:^`, `@suaveplan/logger workspace:^`, `zod catalog:forms`, `@opentelemetry/api catalog:observability`, `tslib catalog:build`.
- [ ] DevDeps: `vitest catalog:testing`, `@vitest/coverage-istanbul catalog:testing`, `@suaveplan/testing workspace:^`.
- [ ] `tsconfig.json` extending `library-node.json`; `vitest.config.ts` with `createTestConfig()`.
- [ ] Scripts: `lint`, `typecheck`, `test`, `test:coverage`, `build`, `docs:check`.

## 2. Types and errors

- [ ] Define all interfaces and Zod schemas in `src/types/health-check.types.ts`.
- [ ] Write `health-check.types.md` (≥200 words, both examples, API reference).
- [ ] `src/error-codes.ts`: three codes; `registerHealthCheckErrorCodes()`; eager call.

## 3. Health registry

- [ ] Implement `HealthRegistry` in `src/registry/health-registry/health-registry.ts`:
  - `register(name, check, options)`: store in internal Map; throw if name already registered.
  - `unregister(name)`: remove; throw `HEALTH_CHECK_NOT_FOUND` if absent.
  - `runAll()`: run all registered checks concurrently (via `Promise.allSettled`); each with `AbortSignal` tied to `timeout`; collect `CheckResult`; compute overall `status` (any critical failure → unhealthy; any non-critical failure → degraded; all pass → healthy). Return `HealthReport`.
  - `runCheck(name)`: run single check with timeout; update cache; return `CheckResult`.
  - Cache: store last `CheckResult` per check; on `runCheck`/`runAll` return cached if within `cacheTtlMs`.
  - OTel counter `health_check.runs_total` with `check_name` and `status`; histogram `health_check.duration_ms`.
- [ ] Write `health-registry.types.ts`.
- [ ] Write `health-registry.test.ts` (≤500 lines): all checks healthy; one critical fails; one non-critical fails (degraded); timeout triggers; cache TTL respected with FakeClock; unregister removes.
- [ ] Write `health-registry.md` (≥200 words, simple + advanced, API reference).

## 4. Health server

- [ ] Implement `HealthServer` in `src/server/health-server/health-server.ts`:
  - Use `Bun.serve` to create a minimal HTTP server.
  - `GET /health`: run all checks; return JSON `HealthReport`; HTTP 200 if healthy/degraded, 503 if unhealthy.
  - `GET /ready`: same logic but only return 503 if any critical check fails.
  - `GET /live`: always return 200 `{ status: 'alive' }` (liveness = process is running).
  - `start()` / `stop()` lifecycle.
  - OTel counter `health_server.requests_total` with `endpoint` and `status_code`.
- [ ] Write `health-server.types.ts`.
- [ ] Write `health-server.test.ts` (≤500 lines): HTTP 200 on all healthy; HTTP 503 on critical failure; custom paths; /live always 200; stop closes server; `{ timeout: 10000 }`.
- [ ] Write `health-server.md` (≥200 words, simple + advanced, API reference).

## 5. Integration tests

- [ ] `tests/integration.test.ts`: real server on random port; fetch `/health`, `/ready`, `/live`; register a DB check that simulates failure; verify 503 on `/health`; `{ timeout: 15000 }`.

## 6. Docs + verify + publish

- [ ] Root `README.md`: Kubernetes probe configuration snippet, quick-start, API table.
- [ ] `bunx turbo lint --filter=@suaveplan/health-check` — zero errors.
- [ ] `bunx turbo typecheck --filter=@suaveplan/health-check` — zero errors.
- [ ] `bunx turbo test --filter=@suaveplan/health-check` — all pass.
- [ ] `bunx turbo test:coverage --filter=@suaveplan/health-check` — 100%.
- [ ] `bun scripts/publish.ts --package @suaveplan/health-check`.
- [ ] Update `CLAUDE.md`; archive to `openspec/archive/2026-04-24-enterprise-server-health-check/`.