diff --git a/app/api/health/route.ts b/app/api/health/route.ts
index 282ff75..e1bd71e 100644
--- a/app/api/health/route.ts
+++ b/app/api/health/route.ts
@@ -1,12 +1,43 @@
 import { NextResponse } from "next/server";
+import { checkAllDependencies, hasDegradedDependency } from "@/lib/health-checks";
 
-// GET /api/health — platform liveness (docs/04). DB/queue wired when provisioned.
+// GET /api/health — liveness (docs/04, BACKLOG P0-3).
+//
+// Fixed finding: this used to hardcode `ok: true` and only ever check
+// *presence* of DATABASE_URL/REDIS_URL, never whether anything was actually
+// reachable -- "an uptime monitor watching HTTP 200 would show green for a
+// dying instance" (docs/architecture/ARCHITECTURE.md). Each dependency below
+// now reports a real state: "ok" (live round trip succeeded), "error"
+// (configured but unreachable -- see `detail`), "not_configured", or
+// "not_integrated" (env var present but no client code reads it -- honest
+// about `queue`, which has no wired Redis client in this repo).
+//
+// This route stays a LIVENESS check: it always answers 200 as long as the
+// process itself can run the handler (that's what "liveness" means -- an
+// external dependency outage is not a reason to restart this instance). The
+// body's `ok` field is the honest signal instead: false whenever a
+// dependency that IS configured is failing. For a readiness gate that DOES
+// fail closed on missing/broken dependencies, see GET /api/ready.
 export async function GET() {
+  const deps = await checkAllDependencies();
+  const degraded = hasDegradedDependency(deps);
+
   return NextResponse.json({
-    ok: true,
+    ok: !degraded,
     service: "0pt-web",
-    db: Boolean(process.env.DATABASE_URL) ? "configured" : "not_configured",
-    queue: Boolean(process.env.REDIS_URL) ? "configured" : "not_configured",
+    db: deps.db.status,
+    queue: deps.queue.status,
+    engine: deps.engine.status,
+    stripe: deps.stripe.status,
+    ...(degraded
+      ? {
+          detail: Object.fromEntries(
+            Object.entries(deps)
+              .filter(([, v]) => v.status === "error")
+              .map(([k, v]) => [k, v.detail]),
+          ),
+        }
+      : {}),
     ts: new Date().toISOString(),
   });
 }
diff --git a/app/api/ready/route.ts b/app/api/ready/route.ts
new file mode 100644
index 0000000..0c37117
--- /dev/null
+++ b/app/api/ready/route.ts
@@ -0,0 +1,32 @@
+import { NextResponse } from "next/server";
+import { checkAllDependencies, isReady } from "@/lib/health-checks";
+
+// GET /api/ready — readiness (BACKLOG P0-3, CD-04/OBS-04: "no /ready route
+// existed at all").
+//
+// Unlike GET /api/health (liveness -- always 200 while the process can
+// respond), this fails closed: 503 whenever a load-bearing dependency isn't
+// both configured AND actually reachable. Point a load balancer / Coolify
+// readiness probe at this route, not /api/health, to stop routing traffic to
+// an instance whose database is down without restarting it.
+//
+// Today the only load-bearing dependency is the database (see
+// `lib/health-checks.ts#isReady`) -- engine/stripe/queue are optional
+// integrations 0pt is designed to run without.
+export async function GET() {
+  const deps = await checkAllDependencies();
+  const ready = isReady(deps);
+
+  return NextResponse.json(
+    {
+      ready,
+      service: "0pt-web",
+      db: deps.db.status,
+      queue: deps.queue.status,
+      engine: deps.engine.status,
+      stripe: deps.stripe.status,
+      ts: new Date().toISOString(),
+    },
+    { status: ready ? 200 : 503 },
+  );
+}
diff --git a/contracts/openapi.yaml b/contracts/openapi.yaml
index 4891b0b..08ced4f 100644
--- a/contracts/openapi.yaml
+++ b/contracts/openapi.yaml
@@ -22,15 +22,35 @@ paths:
   /api/health:
     get:
       operationId: 0pt.health
-      summary: Liveness + dependency state
+      summary: Liveness + real per-dependency state
       x-siax-status: live
+      security: []
       responses:
         "200":
-          description: OK — db/queue rapporterar "configured"/"not_configured"
+          description: Process is alive. Body reports honest per-dependency status (ok/error/not_configured/not_integrated) — see HealthResponse.
           content:
             application/json:
               schema:
                 $ref: "#/components/schemas/HealthResponse"
+  /api/ready:
+    get:
+      operationId: 0pt.ready
+      summary: Readiness — fails closed when a load-bearing dependency is down
+      x-siax-status: live
+      security: []
+      responses:
+        "200":
+          description: Ready to serve real traffic.
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ReadyResponse"
+        "503":
+          description: Not ready — a load-bearing dependency is not configured/reachable.
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ReadyResponse"
   /api/estimates:
     post:
       operationId: 0pt.estimate_order
@@ -401,7 +421,18 @@ components:
               type: string
     HealthResponse:
       type: object
-      required: [ok, service, db, queue, ts]
+      description: >
+        db/engine/stripe report a real dependency probe (BACKLOG P0-3): "ok"
+        means a live round trip succeeded, "error" means it was configured
+        but unreachable (see `detail`), "not_configured" means the env var
+        is unset. `queue` can only ever be "not_configured" or
+        "not_integrated" -- no Redis client is wired in this repo, so
+        presence of REDIS_URL is reported honestly rather than faking a
+        connectivity check. `ok` is true only when no configured dependency
+        is in "error". This is a LIVENESS check: HTTP status stays 200
+        whenever the process can respond, regardless of dependency state --
+        see /api/ready for the readiness gate that fails closed.
+      required: [ok, service, db, queue, engine, stripe, ts]
       properties:
         ok:
           type: boolean
@@ -409,10 +440,49 @@ components:
           type: string
         db:
           type: string
-          enum: [configured, not_configured]
+          enum: [ok, error, not_configured]
         queue:
           type: string
-          enum: [configured, not_configured]
+          enum: [not_configured, not_integrated]
+        engine:
+          type: string
+          enum: [ok, error, not_configured]
+        stripe:
+          type: string
+          enum: [ok, error, not_configured]
+        detail:
+          type: object
+          description: Present only when `ok` is false -- one-line error message per failing dependency.
+          additionalProperties:
+            type: string
+        ts:
+          type: string
+          format: date-time
+    ReadyResponse:
+      type: object
+      description: >
+        Readiness (BACKLOG P0-3: "no /ready route existed"). Fails closed --
+        503 whenever a load-bearing dependency (today: only `db`) is not
+        both configured and reachable. Point a load balancer / Coolify
+        readiness probe here, not at /api/health.
+      required: [ready, service, db, queue, engine, stripe, ts]
+      properties:
+        ready:
+          type: boolean
+        service:
+          type: string
+        db:
+          type: string
+          enum: [ok, error, not_configured]
+        queue:
+          type: string
+          enum: [not_configured, not_integrated]
+        engine:
+          type: string
+          enum: [ok, error, not_configured]
+        stripe:
+          type: string
+          enum: [ok, error, not_configured]
         ts:
           type: string
           format: date-time
diff --git a/docs/architecture/ARCHITECTURE.md b/docs/architecture/ARCHITECTURE.md
index 788ebc0..906e9e3 100644
--- a/docs/architecture/ARCHITECTURE.md
+++ b/docs/architecture/ARCHITECTURE.md
@@ -132,6 +132,7 @@ Risknivå = SIAX L0–L5-taxonomin, bedömd av mig utifrån vad handlern gör.
 | Operation | Metod/sökväg | Risknivå | Kräver godkännande |
 |---|---|---|---|
 | Liveness | `GET /api/health` | L0 | Nej (avsiktligt) |
+| Readiness | `GET /api/ready` | L0 | Nej (avsiktligt) |
 | Prisestimat | `POST /api/estimates` | L1 | Nej |
 | Katalog / källor / fordon | `GET /api/{catalog,sources,vehicles}` | L1 | Nej |
 | Sanktions-/PEP-screening | `GET /api/screen?q=` | L2 | Nej — proxar mot OpenSanctions |
@@ -240,11 +241,20 @@ inget sådant jobb, ingen TTL, ingen `DELETE`-väg och ingen radering finns i ko
 ## 6. Drift
 
 ### Hälsokontroll
-`GET /api/health` → `{ok, service:"0pt-web", db, queue, ts}`. Den svarar **alltid
-`ok:true`** oavsett om databasen finns — den rapporterar bara `"not_configured"`
-i ett fält. En uptime-monitor som tittar på HTTP 200 kommer därför visa grönt
-för en instans utan databas, vilket är exakt vad som gäller idag. Engine har ett
-separat `GET /health`.
+**Fixat (BACKLOG P0-3):** `GET /api/health` → `{ok, service:"0pt-web", db, queue,
+engine, stripe, ts}`. `db`/`engine`/`stripe` rapporterar nu en riktig
+beroendeprobe (`lib/health-checks.ts`): `"ok"` = lyckad live-anrop, `"error"` =
+konfigurerad men onåbar (se `detail`), `"not_configured"` = env-variabel ej
+satt. `queue` kan bara vara `"not_configured"`/`"not_integrated"` — ingen
+Redis-klient finns i repot, så en satt `REDIS_URL` rapporteras ärligt i stället
+för att låtsas testa en anslutning som aldrig görs. `ok` är `true` endast när
+ingen konfigurerad dependency ligger i `"error"`. HTTP-statusen är fortsatt
+alltid 200 (liveness — processen svarar) oavsett dependency-läge; en extern
+beroendekrasch ska inte omstarta instansen. Ny `GET /api/ready` failar stängt
+(503) när databasen (den enda lastbärande dependencyn idag) inte både är
+konfigurerad och nåbar — peka en Coolify/lastbalanserar-readiness-probe dit,
+inte mot `/api/health`. Engine har ett separat `GET /health` som `checkEngine()`
+nu faktiskt anropar (tidigare kollades bara `ENGINE_URL`-närvaro).
 
 ### Loggar
 Ingen strukturerad loggning. `console.warn` i `src/auth/context.ts` är den enda
diff --git a/docs/slo.md b/docs/slo.md
index 5773ef0..407efbb 100644
--- a/docs/slo.md
+++ b/docs/slo.md
@@ -7,7 +7,8 @@
 
 | SLO | Mål | Nuläge (2026-08-10) |
 |---|---|---|
-| `/api/health` (liveness) | 99,9 % | ✅ 200 (men alltid `ok:true` — readiness saknas, se D2) |
+| `/api/health` (liveness) | 99,9 % | ✅ 200; `ok` speglar nu en riktig per-dependency-probe (fixat BACKLOG P0-3) |
+| `/api/ready` (readiness) | 99,5 % | ✅ ny (BACKLOG P0-3) — 503 när `db` inte är konfigurerad+nåbar |
 | Orderflöde `/api/orders` | 99,5 % | ⚠️ fungerar utan DB (in-memory), data försvinner vid restart |
 | Capability-API `/api/0pt/*` | 99,5 % | ⚠️ live 200 anonymt (lucka S1) — målbild: 401 utan token |
 | Engine (FastAPI, när deployad) | 99,0 % | ej deployad (EJ VERIFIERAT) |
diff --git a/lib/health-checks.ts b/lib/health-checks.ts
new file mode 100644
index 0000000..2e737e0
--- /dev/null
+++ b/lib/health-checks.ts
@@ -0,0 +1,174 @@
+// Dependency health probes shared by GET /api/health (liveness) and
+// GET /api/ready (readiness). See docs/architecture/ARCHITECTURE.md
+// "Hälsokontroll" and BACKLOG P0-3 for the finding this fixes: the old
+// /api/health handler only ever checked *presence* of an env var and
+// hardcoded `ok: true` regardless of whether anything was actually
+// reachable -- "an uptime monitor watching HTTP 200 would show green for a
+// dying instance". Each check below returns one of four honest states:
+//
+//   "ok"             -- configured AND a live round trip succeeded.
+//   "error"          -- configured but the round trip failed (bad creds,
+//                       host unreachable, timeout, ...). detail carries the
+//                       underlying error message.
+//   "not_configured" -- no env var set. Not a failure by itself (0pt is
+//                       designed to build/boot with everything unset).
+//   "not_integrated" -- env var IS set, but no client code in this repo
+//                       actually uses it (currently only REDIS_URL/queue --
+//                       see .env.example). Reporting "ok" here would be a
+//                       fabricated check; reporting "not_configured" would
+//                       hide that a value was provided. This is its own
+//                       honest state rather than either of those two.
+import { dbUrl, getSql } from "./db";
+import { getStripe } from "./stripe";
+import { hasEngine } from "./engine";
+
+export type DepStatus = "ok" | "error" | "not_configured" | "not_integrated";
+
+export interface DepResult {
+  status: DepStatus;
+  detail?: string;
+  latencyMs?: number;
+}
+
+export const DEFAULT_TIMEOUT_MS = 2000;
+
+function errMessage(err: unknown): string {
+  return err instanceof Error ? err.message : String(err);
+}
+
+function withTimeout<T>(promise: Promise<T>, ms: number, label: string): Promise<T> {
+  return new Promise<T>((resolve, reject) => {
+    const timer = setTimeout(() => reject(new Error(`${label} timed out after ${ms}ms`)), ms);
+    promise.then(
+      (v) => {
+        clearTimeout(timer);
+        resolve(v);
+      },
+      (e) => {
+        clearTimeout(timer);
+        reject(e);
+      },
+    );
+  });
+}
+
+// Minimal shape of the one call site needs from the postgres client --
+// matches `postgres`'s tagged-template callable, but kept narrow so tests
+// can inject a fake without constructing a real `postgres.Sql`.
+export type SqlPing = (strings: TemplateStringsArray, ...values: unknown[]) => Promise<unknown>;
+
+/**
+ * Postgres reachability. `select 1` is the standard zero-cost liveness query
+ * -- it never touches application tables, so it can't fail on schema drift.
+ */
+export async function checkDatabase(
+  sqlClient: SqlPing | null = getSql() as unknown as SqlPing | null,
+  timeoutMs: number = DEFAULT_TIMEOUT_MS,
+): Promise<DepResult> {
+  if (!dbUrl() || !sqlClient) return { status: "not_configured" };
+  const start = Date.now();
+  try {
+    await withTimeout(sqlClient`select 1`, timeoutMs, "database ping");
+    return { status: "ok", latencyMs: Date.now() - start };
+  } catch (err) {
+    return { status: "error", detail: errMessage(err), latencyMs: Date.now() - start };
+  }
+}
+
+/**
+ * FastAPI data engine (services/api) reachability via its own `GET /health`
+ * (services/api/orchestrator/main.py). Uses a real HTTP round trip, not just
+ * `hasEngine()` presence -- ENGINE_URL pointing at a dead host used to read
+ * as healthy.
+ */
+export async function checkEngine(
+  fetchImpl: typeof fetch = fetch,
+  timeoutMs: number = DEFAULT_TIMEOUT_MS,
+): Promise<DepResult> {
+  if (!hasEngine()) return { status: "not_configured" };
+  const base = process.env.ENGINE_URL as string;
+  const start = Date.now();
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), timeoutMs);
+  try {
+    const res = await fetchImpl(`${base}/health`, {
+      signal: controller.signal,
+      cache: "no-store",
+      headers: { "X-Internal-Token": process.env.INTERNAL_TOKEN ?? "" },
+    });
+    if (!res.ok) {
+      return { status: "error", detail: `HTTP ${res.status}`, latencyMs: Date.now() - start };
+    }
+    return { status: "ok", latencyMs: Date.now() - start };
+  } catch (err) {
+    return { status: "error", detail: errMessage(err), latencyMs: Date.now() - start };
+  } finally {
+    clearTimeout(timer);
+  }
+}
+
+// Minimal shape of the one Stripe call this needs -- matches
+// `Stripe#balance.retrieve`, kept narrow so tests can inject a fake instead
+// of constructing a real Stripe client.
+export interface StripeBalanceClient {
+  balance: { retrieve(): Promise<unknown> };
+}
+
+/**
+ * Stripe reachability. `balance.retrieve()` is Stripe's documented
+ * lightweight "is this key valid and can I reach the API" call -- it makes
+ * one real API round trip (catching e.g. a revoked/placeholder key) without
+ * mutating anything or touching a specific resource.
+ */
+export async function checkStripe(
+  client: StripeBalanceClient | null = getStripe() as unknown as StripeBalanceClient | null,
+  timeoutMs: number = DEFAULT_TIMEOUT_MS,
+): Promise<DepResult> {
+  if (!client) return { status: "not_configured" };
+  const start = Date.now();
+  try {
+    await withTimeout(client.balance.retrieve(), timeoutMs, "stripe balance.retrieve");
+    return { status: "ok", latencyMs: Date.now() - start };
+  } catch (err) {
+    return { status: "error", detail: errMessage(err), latencyMs: Date.now() - start };
+  }
+}
+
+/**
+ * Redis/queue: presence-only, honestly. No queue client library is a
+ * dependency of this package (grep-verified against package.json) and no
+ * code path in this repo reads REDIS_URL to open a connection -- so there is
+ * no real check to run. Reporting "ok" would fabricate a probe that doesn't
+ * exist; this reports "not_integrated" instead of silently upgrading to a
+ * pretend pass.
+ */
+export function checkQueue(): DepResult {
+  return { status: process.env.REDIS_URL ? "not_integrated" : "not_configured" };
+}
+
+export interface DependencyResults {
+  db: DepResult;
+  engine: DepResult;
+  stripe: DepResult;
+  queue: DepResult;
+}
+
+export async function checkAllDependencies(): Promise<DependencyResults> {
+  const [db, engine, stripe] = await Promise.all([checkDatabase(), checkEngine(), checkStripe()]);
+  return { db, engine, stripe, queue: checkQueue() };
+}
+
+/** True when any dependency that IS configured/integrated is broken. */
+export function hasDegradedDependency(deps: DependencyResults): boolean {
+  return Object.values(deps).some((d) => d.status === "error");
+}
+
+/**
+ * Readiness (unlike liveness) treats "not configured" for the deps this app
+ * cannot serve real traffic without as not-ready too. Only `db` is load-bearing
+ * today -- engine/stripe/queue are optional integrations the app is designed
+ * to run without (see .env.example).
+ */
+export function isReady(deps: DependencyResults): boolean {
+  return deps.db.status === "ok";
+}
diff --git a/middleware.ts b/middleware.ts
index acecf6a..990ac9f 100644
--- a/middleware.ts
+++ b/middleware.ts
@@ -33,7 +33,11 @@ export const config = {
   matcher: ['/api/0pt/:path*'],
 };
 
-const EXEMPT_PATTERNS: RegExp[] = [/^\/api\/health(\/|$)/, /^\/api\/admin\/metrics(\/|$)/];
+const EXEMPT_PATTERNS: RegExp[] = [
+  /^\/api\/health(\/|$)/,
+  /^\/api\/ready(\/|$)/,
+  /^\/api\/admin\/metrics(\/|$)/,
+];
 
 export async function middleware(req: NextRequest): Promise<NextResponse> {
   const path = req.nextUrl.pathname;
diff --git a/tests/api/health.test.ts b/tests/api/health.test.ts
new file mode 100644
index 0000000..04aaeda
--- /dev/null
+++ b/tests/api/health.test.ts
@@ -0,0 +1,70 @@
+/**
+ * Route-level regression test for GET /api/health (BACKLOG P0-3): the old
+ * handler hardcoded `ok: true` regardless of dependency state. These tests
+ * cover the default (nothing configured) baseline against the real route
+ * handler; per-dependency ok/error branching is covered at the unit level in
+ * tests/lib/health-checks.test.ts (dependency-injected, no network/DB
+ * needed).
+ */
+import { describe, it, expect, beforeEach, afterEach } from "vitest";
+import { GET as healthGET } from "@/app/api/health/route";
+
+describe("GET /api/health", () => {
+  const savedEnv = {
+    DATABASE_URL: process.env.DATABASE_URL,
+    POSTGRES_URL: process.env.POSTGRES_URL,
+    ENGINE_URL: process.env.ENGINE_URL,
+    STRIPE_SECRET_KEY: process.env.STRIPE_SECRET_KEY,
+    REDIS_URL: process.env.REDIS_URL,
+  };
+
+  beforeEach(() => {
+    delete process.env.DATABASE_URL;
+    delete process.env.POSTGRES_URL;
+    delete process.env.ENGINE_URL;
+    delete process.env.STRIPE_SECRET_KEY;
+    delete process.env.REDIS_URL;
+  });
+
+  afterEach(() => {
+    for (const [k, v] of Object.entries(savedEnv)) {
+      if (v === undefined) delete process.env[k];
+      else process.env[k] = v;
+    }
+  });
+
+  it("REGRESSION: always returns HTTP 200 (liveness), but `ok` now reflects a real per-dependency check rather than a hardcoded true", async () => {
+    const res = await healthGET();
+    expect(res.status).toBe(200);
+    const body = await res.json();
+    // With nothing configured, nothing can be degraded -- ok:true here is
+    // now an honest conclusion, not a hardcoded literal.
+    expect(body.ok).toBe(true);
+    expect(body.service).toBe("0pt-web");
+  });
+
+  it("reports not_configured (not the old flat 'configured'/'not_configured' guess) for every unset dependency", async () => {
+    const res = await healthGET();
+    const body = await res.json();
+    expect(body.db).toBe("not_configured");
+    expect(body.engine).toBe("not_configured");
+    expect(body.stripe).toBe("not_configured");
+    expect(body.queue).toBe("not_configured");
+  });
+
+  it("reports queue as not_integrated (never a fabricated ok) when REDIS_URL is set but unused", async () => {
+    process.env.REDIS_URL = "redis://localhost:6379";
+    const res = await healthGET();
+    const body = await res.json();
+    expect(body.queue).toBe("not_integrated");
+    // Not wiring a real check for an unused integration is not itself a
+    // degradation -- overall liveness stays ok.
+    expect(body.ok).toBe(true);
+  });
+
+  it("response includes a ts timestamp", async () => {
+    const res = await healthGET();
+    const body = await res.json();
+    expect(new Date(body.ts).toString()).not.toBe("Invalid Date");
+  });
+});
diff --git a/tests/api/ready.test.ts b/tests/api/ready.test.ts
new file mode 100644
index 0000000..19a5c5b
--- /dev/null
+++ b/tests/api/ready.test.ts
@@ -0,0 +1,34 @@
+/**
+ * Route-level test for GET /api/ready (BACKLOG P0-3: "no /ready route
+ * existed at all"). Unlike /api/health, readiness fails closed: 503 when the
+ * load-bearing dependency (db) is not both configured and reachable.
+ */
+import { describe, it, expect, beforeEach, afterEach } from "vitest";
+import { GET as readyGET } from "@/app/api/ready/route";
+
+describe("GET /api/ready", () => {
+  const savedEnv = {
+    DATABASE_URL: process.env.DATABASE_URL,
+    POSTGRES_URL: process.env.POSTGRES_URL,
+  };
+
+  beforeEach(() => {
+    delete process.env.DATABASE_URL;
+    delete process.env.POSTGRES_URL;
+  });
+
+  afterEach(() => {
+    for (const [k, v] of Object.entries(savedEnv)) {
+      if (v === undefined) delete process.env[k];
+      else process.env[k] = v;
+    }
+  });
+
+  it("fails closed with 503 when the database is not configured", async () => {
+    const res = await readyGET();
+    expect(res.status).toBe(503);
+    const body = await res.json();
+    expect(body.ready).toBe(false);
+    expect(body.db).toBe("not_configured");
+  });
+});
diff --git a/tests/lib/health-checks.test.ts b/tests/lib/health-checks.test.ts
new file mode 100644
index 0000000..406b339
--- /dev/null
+++ b/tests/lib/health-checks.test.ts
@@ -0,0 +1,185 @@
+/**
+ * Unit tests for the dependency probes behind GET /api/health + GET
+ * /api/ready (BACKLOG P0-3). Each check is exercised via dependency
+ * injection (fake sql/fetch/stripe clients) rather than real network I/O,
+ * matching the fake-over-mock-global convention used elsewhere in this repo
+ * (e.g. tests/p0/document-intelligence-adapter.test.ts).
+ */
+import { describe, it, expect, afterEach } from "vitest";
+import {
+  checkDatabase,
+  checkEngine,
+  checkStripe,
+  checkQueue,
+  hasDegradedDependency,
+  isReady,
+  type DependencyResults,
+  type SqlPing,
+} from "@/lib/health-checks";
+
+function jsonResponse(body: unknown, status = 200): Response {
+  return {
+    ok: status < 400,
+    status,
+    json: async () => body,
+  } as unknown as Response;
+}
+
+describe("checkDatabase", () => {
+  const saved = process.env.DATABASE_URL;
+  afterEach(() => {
+    if (saved === undefined) delete process.env.DATABASE_URL;
+    else process.env.DATABASE_URL = saved;
+  });
+
+  it("reports not_configured when DATABASE_URL is unset, without calling the client", async () => {
+    delete process.env.DATABASE_URL;
+    let called = false;
+    const fakeSql: SqlPing = async () => {
+      called = true;
+      return [{ "?column?": 1 }];
+    };
+    const result = await checkDatabase(fakeSql);
+    expect(result.status).toBe("not_configured");
+    expect(called).toBe(false);
+  });
+
+  it("reports ok when the ping round trip succeeds", async () => {
+    process.env.DATABASE_URL = "postgres://user:pass@localhost:5432/opt";
+    const fakeSql: SqlPing = async () => [{ "?column?": 1 }];
+    const result = await checkDatabase(fakeSql);
+    expect(result.status).toBe("ok");
+    expect(typeof result.latencyMs).toBe("number");
+  });
+
+  it("reports error with the driver message when the ping fails", async () => {
+    process.env.DATABASE_URL = "postgres://user:pass@localhost:5432/opt";
+    const fakeSql: SqlPing = async () => {
+      throw new Error("ECONNREFUSED 127.0.0.1:5432");
+    };
+    const result = await checkDatabase(fakeSql);
+    expect(result.status).toBe("error");
+    expect(result.detail).toContain("ECONNREFUSED");
+  });
+
+  it("reports error on timeout rather than hanging", async () => {
+    process.env.DATABASE_URL = "postgres://user:pass@localhost:5432/opt";
+    const fakeSql: SqlPing = () => new Promise(() => {}); // never resolves
+    const result = await checkDatabase(fakeSql, 20);
+    expect(result.status).toBe("error");
+    expect(result.detail).toContain("timed out");
+  });
+
+  it("reports not_configured when DATABASE_URL is set but no client is available", async () => {
+    process.env.DATABASE_URL = "postgres://user:pass@localhost:5432/opt";
+    const result = await checkDatabase(null);
+    expect(result.status).toBe("not_configured");
+  });
+});
+
+describe("checkEngine", () => {
+  const saved = process.env.ENGINE_URL;
+  afterEach(() => {
+    if (saved === undefined) delete process.env.ENGINE_URL;
+    else process.env.ENGINE_URL = saved;
+  });
+
+  it("reports not_configured when ENGINE_URL is unset", async () => {
+    delete process.env.ENGINE_URL;
+    const result = await checkEngine(async () => jsonResponse({ ok: true }));
+    expect(result.status).toBe("not_configured");
+  });
+
+  it("reports ok when the engine's /health responds 2xx", async () => {
+    process.env.ENGINE_URL = "http://engine.local:8000";
+    const fetchMock = (async (url: string) => {
+      expect(url).toBe("http://engine.local:8000/health");
+      return jsonResponse({ ok: true });
+    }) as unknown as typeof fetch;
+    const result = await checkEngine(fetchMock);
+    expect(result.status).toBe("ok");
+  });
+
+  it("reports error when the engine responds non-2xx", async () => {
+    process.env.ENGINE_URL = "http://engine.local:8000";
+    const result = await checkEngine(async () => jsonResponse({}, 500));
+    expect(result.status).toBe("error");
+    expect(result.detail).toContain("500");
+  });
+
+  it("reports error when the fetch throws (host unreachable)", async () => {
+    process.env.ENGINE_URL = "http://engine.local:8000";
+    const result = await checkEngine(async () => {
+      throw new Error("fetch failed");
+    });
+    expect(result.status).toBe("error");
+  });
+});
+
+describe("checkStripe", () => {
+  it("reports not_configured when no client is available (no STRIPE_SECRET_KEY)", async () => {
+    const result = await checkStripe(null);
+    expect(result.status).toBe("not_configured");
+  });
+
+  it("reports ok when balance.retrieve() succeeds", async () => {
+    const result = await checkStripe({ balance: { retrieve: async () => ({ available: [] }) } });
+    expect(result.status).toBe("ok");
+  });
+
+  it("reports error when balance.retrieve() rejects (e.g. revoked key)", async () => {
+    const result = await checkStripe({
+      balance: {
+        retrieve: async () => {
+          throw new Error("Invalid API Key provided");
+        },
+      },
+    });
+    expect(result.status).toBe("error");
+    expect(result.detail).toContain("Invalid API Key");
+  });
+});
+
+describe("checkQueue", () => {
+  const saved = process.env.REDIS_URL;
+  afterEach(() => {
+    if (saved === undefined) delete process.env.REDIS_URL;
+    else process.env.REDIS_URL = saved;
+  });
+
+  it("never claims ok — only not_configured or not_integrated (no Redis client wired in this repo)", () => {
+    delete process.env.REDIS_URL;
+    expect(checkQueue().status).toBe("not_configured");
+    process.env.REDIS_URL = "redis://localhost:6379";
+    expect(checkQueue().status).toBe("not_integrated");
+  });
+});
+
+describe("hasDegradedDependency / isReady", () => {
+  function deps(overrides: Partial<DependencyResults> = {}): DependencyResults {
+    return {
+      db: { status: "not_configured" },
+      engine: { status: "not_configured" },
+      stripe: { status: "not_configured" },
+      queue: { status: "not_configured" },
+      ...overrides,
+    };
+  }
+
+  it("hasDegradedDependency is false when nothing is configured", () => {
+    expect(hasDegradedDependency(deps())).toBe(false);
+  });
+
+  it("hasDegradedDependency is true when any dependency errored", () => {
+    expect(hasDegradedDependency(deps({ engine: { status: "error", detail: "boom" } }))).toBe(true);
+  });
+
+  it("isReady is false when db is not ok, even if nothing else is broken", () => {
+    expect(isReady(deps())).toBe(false);
+    expect(isReady(deps({ db: { status: "error" } }))).toBe(false);
+  });
+
+  it("isReady is true once db is ok, regardless of optional integrations", () => {
+    expect(isReady(deps({ db: { status: "ok" } }))).toBe(true);
+  });
+});