diff --git a/server/src/__tests__/workspace-runtime.test.ts b/server/src/__tests__/workspace-runtime.test.ts
index 61c612bfdc..ff33318d5f 100644
--- a/server/src/__tests__/workspace-runtime.test.ts
+++ b/server/src/__tests__/workspace-runtime.test.ts
@@ -3294,6 +3294,58 @@ describe("ensureRuntimeServicesForRun", () => {
     expect(services).toEqual([]);
   });
 
+  it("requires Paperclip dev runtime services to pass /api/health readiness", async () => {
+    const workspaceRoot = await fs.mkdtemp(path.join(os.tmpdir(), "paperclip-runtime-health-"));
+    const workspace = buildWorkspace(workspaceRoot);
+    const runId = "run-paperclip-health";
+    const serviceCommand =
+      "node -e \"const http=require('node:http'); http.createServer((req,res)=>{ if (req.url==='/api/health') { res.statusCode=503; res.end('database_unreachable'); return; } res.end('ok'); }).listen(Number(process.env.PORT), '127.0.0.1')\"";
+
+    try {
+      await expect(
+        ensureRuntimeServicesForRun({
+          runId,
+          agent: {
+            id: "agent-1",
+            name: "Codex Coder",
+            companyId: "company-1",
+          },
+          issue: null,
+          workspace,
+          config: {
+            workspaceRuntime: {
+              services: [
+                {
+                  name: "paperclip-dev",
+                  command: serviceCommand,
+                  cwd: ".",
+                  port: { type: "auto" },
+                  readiness: {
+                    type: "http",
+                    urlTemplate: "http://127.0.0.1:{{port}}",
+                    timeoutSec: 3,
+                    intervalMs: 100,
+                  },
+                  expose: {
+                    type: "url",
+                    urlTemplate: "http://127.0.0.1:{{port}}",
+                  },
+                  lifecycle: "shared",
+                  stopPolicy: {
+                    type: "manual",
+                  },
+                },
+              ],
+            },
+          },
+          adapterEnv: {},
+        }),
+      ).rejects.toThrow(/Readiness check failed for http:\/\/127\.0\.0\.1:\d+\/api\/health: received HTTP 503/);
+    } finally {
+      await releaseRuntimeServicesForRun(runId);
+    }
+  });
+
   it("reuses shared runtime services across runs and starts a new service after release", async () => {
     const workspaceRoot = await fs.mkdtemp(path.join(os.tmpdir(), "paperclip-runtime-workspace-"));
     const workspace = buildWorkspace(workspaceRoot);
diff --git a/server/src/services/workspace-runtime.ts b/server/src/services/workspace-runtime.ts
index 3a062137be..d32ae03c6c 100644
--- a/server/src/services/workspace-runtime.ts
+++ b/server/src/services/workspace-runtime.ts
@@ -2867,18 +2867,27 @@ export function resolveWorkspaceRuntimeReadinessTimeoutSec(service: Record<strin
 
 async function waitForReadiness(input: {
   service: Record<string, unknown>;
+  serviceName?: string | null;
+  command?: string | null;
   url: string | null;
 }) {
   const readiness = parseObject(input.service.readiness);
   const readinessType = asString(readiness.type, "");
   if (readinessType !== "http" || !input.url) return;
+  const readinessUrl = resolveRuntimeServiceHealthUrl(input.url, {
+    serviceName: input.serviceName,
+    command: input.command,
+  });
+  if (!readinessUrl) {
+    throw new Error(`Readiness check failed: could not resolve health URL for ${input.url}`);
+  }
   const timeoutSec = resolveWorkspaceRuntimeReadinessTimeoutSec(input.service);
   const intervalMs = Math.max(100, asNumber(readiness.intervalMs, 500));
   const deadline = Date.now() + timeoutSec * 1000;
   let lastError = "service did not become ready";
   while (Date.now() < deadline) {
     try {
-      const response = await fetch(input.url);
+      const response = await fetch(readinessUrl);
       if (response.ok) return;
       lastError = `received HTTP ${response.status}`;
     } catch (err) {
@@ -2886,7 +2895,7 @@ async function waitForReadiness(input: {
     }
     await delay(intervalMs);
   }
-  throw new Error(`Readiness check failed for ${input.url}: ${lastError}`);
+  throw new Error(`Readiness check failed for ${readinessUrl}: ${lastError}`);
 }
 
 function isPaperclipDevRuntimeService(input: { serviceName?: string | null; command?: string | null }) {
@@ -2924,7 +2933,7 @@ async function isRuntimeServiceUrlHealthy(
 ) {
   if (!url) return true;
   const healthUrl = resolveRuntimeServiceHealthUrl(url, input);
-  if (!healthUrl) return true;
+  if (!healthUrl) return false;
   try {
     const response = await fetch(healthUrl, { signal: AbortSignal.timeout(2_000) });
     return response.ok;
@@ -3294,7 +3303,7 @@ async function startLocalRuntimeService(input: {
 
   try {
     await Promise.race([
-      waitForReadiness({ service: input.service, url }),
+      waitForReadiness({ service: input.service, serviceName, command, url }),
       spawnErrorPromise,
     ]);
   } catch (err) {