fix(api): return coded 503 when rate limiter fails on keeper health

api/__tests__/handlers.test.ts

@@ -1318,6 +1318,27 @@ describe("GET /api/v1/keepers/health", () => {
       lastSuccessMs: null,
     });
   });
+
+  it("returns 503 when the upstream rate limiter fails", async () => {
+    vi.mocked(checkRateLimit).mockRejectedValueOnce(
+      new Error("Upstash timeout")
+    );
+
+    const res = makeRes();
+    await keepersHandler(
+      fakeReq({
+        query: { action: "health" },
+        method: "GET",
+        headers: {},
+      }),
+      res
+    );
+
+    expect(res.statusCode).toBe(503);
+    expect(res.body).toEqual({
+      error: "Rate limiter unavailable; refusing to run",
+    });
+  });
 });
 
 describe("GET /api/v1/admin/vault-state", () => {

api/v1/keepers/[action].ts

@@ -43,7 +43,14 @@ export default async function handler(req: VercelRequest, res: VercelResponse) {
 
   if (action === "health") {
     if (applyCors(req, res)) return;
-    if (!(await checkRateLimit(req, res))) return;
+    try {
+      if (!(await checkRateLimit(req, res))) return;
+    } catch (err) {
+      console.error("[keepers/health] rate limit check failed:", err);
+      return res
+        .status(503)
+        .json({ error: "Rate limiter unavailable; refusing to run" });
+    }
     const result = await handleGetKeeperHealth();
     if (result.error) console.error("[keepers/health] error:", result.error);
     res.setHeader("Cache-Control", "no-store");