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openspec/changes/enterprise-server-health-check/proposal.md

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+# OpenSpec Change: enterprise-server-health-check
+
+- **Change ID**: enterprise-server-health-check
+- **Package**: `@suaveplan/health-check`
+- **Category**: server/infra
+- **Target path**: `server/infra/health-check`
+- **Status**: PROPOSED
+- **Date**: 2026-04-24
+- **Reference spec**: `/mnt/s/web/suaveplan/enterprise/health-check.md`
+
+---
+
+## Summary
+
+Deliver `@suaveplan/health-check` on the genesis branch from scratch at enterprise quality. The package provides a framework-agnostic health check system that exposes `/health`, `/ready`, and `/live` HTTP endpoints following Kubernetes probe conventions. A `HealthRegistry` holds named `HealthCheck` functions; an `HealthServer` runs a lightweight HTTP server returning structured JSON responses. Individual checks can have configurable timeouts, retry counts, and cache TTLs. Genesis adds Zod schemas, `@suaveplan/error` codes, OTel counters per check result, structured logging, and 100% test coverage via both unit and integration tests.
+
+---
+
+## Current-state audit (genesis)
+
+Does not exist on genesis — fresh build.
+
+---
+
+## Available workspace deps on genesis
+
+| Package | Role |
+|---|---|
+| `@suaveplan/error` (`workspace:^`) | Typed `HEALTH_CHECK.*` error codes |
+| `@suaveplan/types` (`workspace:^`) | `LoggerLike`, `Clock` |
+| `@suaveplan/logger` (`workspace:^`) | Structured logs |
+| `zod` (`catalog:forms`) | Options validation |
+| `@opentelemetry/api` (`catalog:observability`) | Counters + histograms |
+| `tslib` (`catalog:build`) | Runtime helpers |
+
+---
+
+## Public API surface
+
+```ts
+class HealthRegistry {
+  register(name: string, check: HealthCheckFn, options?: CheckOptions): void
+  unregister(name: string): void
+  runAll(): Promise<HealthReport>
+  runCheck(name: string): Promise<CheckResult>
+}
+
+class HealthServer {
+  constructor(registry: HealthRegistry, options?: HealthServerOptions)
+  start(): Promise<void>
+  stop(): Promise<void>
+  address(): { host: string; port: number } | undefined
+}
+
+function createHealthRegistry(): HealthRegistry
+function createHealthServer(registry: HealthRegistry, options?: HealthServerOptions): HealthServer
+
+type HealthCheckFn = (signal: AbortSignal) => Promise<void>   // throws = unhealthy
+
+interface CheckOptions {
+  timeout?: number        // ms, default: 5000
+  critical?: boolean      // if true, failure marks overall status 'unhealthy'
+  cacheTtlMs?: number     // reuse last result for this duration
+}
+
+interface CheckResult {
+  name: string
+  status: 'healthy' | 'unhealthy' | 'degraded'
+  duration: number        // ms
+  error?: string
+  cachedAt?: number
+}
+
+interface HealthReport {
+  status: 'healthy' | 'unhealthy' | 'degraded'
+  checks: CheckResult[]
+  timestamp: number
+}
+
+interface HealthServerOptions {
+  port?: number          // default: 3001
+  host?: string          // default: '0.0.0.0'
+  path?: {
+    health?: string      // default: '/health'
+    ready?: string       // default: '/ready'
+    live?: string        // default: '/live'
+  }
+  logger?: LoggerLike
+}
+
+type HealthCheckErrorCode =
+  | 'HEALTH_CHECK_TIMEOUT'
+  | 'HEALTH_CHECK_NOT_FOUND'
+  | 'HEALTH_SERVER_START_FAILED'
+
+function registerHealthCheckErrorCodes(): void
+```
+
+---
+
+## File layout
+
+```text
+server/infra/health-check/
+  package.json
+  tsconfig.json
+  vitest.config.ts
+  src/
+    index.ts
+    error-codes.ts
+    constants/index.ts
+    types/
+      health-check.types.ts
+      health-check.types.md
+    registry/
+      health-registry/
+        health-registry.ts
+        health-registry.md
+        health-registry.types.ts
+        health-registry.test.ts
+        index.ts
+    server/
+      health-server/
+        health-server.ts
+        health-server.md
+        health-server.types.ts
+        health-server.test.ts
+        index.ts
+  tests/
+    integration.test.ts
+```
+
+---
+
+## Impact
+
+Downstream: all server packages use `@suaveplan/health-check` to register their own checks. This is a core infrastructure primitive.
+
+**Prerequisites on Verdaccio**: `@suaveplan/error`, `@suaveplan/types`, `@suaveplan/logger`.