diff --git a/src/agents/embedded-agent-runner/openrouter-model-capabilities.test.ts b/src/agents/embedded-agent-runner/openrouter-model-capabilities.test.ts
index 37d385565a18..270d74e7060b 100644
--- a/src/agents/embedded-agent-runner/openrouter-model-capabilities.test.ts
+++ b/src/agents/embedded-agent-runner/openrouter-model-capabilities.test.ts
@@ -105,6 +105,21 @@ describe("openrouter-model-capabilities", () => {
     });
   });
 
+  it("cancels failed OpenRouter catalog response bodies", async () => {
+    await withOpenRouterStateDir(async () => {
+      const response = new Response("temporarily unavailable", { status: 503 });
+      const cancel = vi.spyOn(response.body!, "cancel").mockResolvedValue(undefined);
+      const fetchSpy = vi.fn(async () => response);
+      vi.stubGlobal("fetch", fetchSpy);
+
+      const module = await importOpenRouterModelCapabilities("failed-catalog-response");
+      await module.loadOpenRouterModelCapabilities("acme/missing-model");
+
+      expect(fetchSpy).toHaveBeenCalledTimes(1);
+      expect(cancel).toHaveBeenCalledOnce();
+    });
+  });
+
   it("uses endpoint-specific OpenRouter context length when top_provider reports one", async () => {
     await withOpenRouterStateDir(async () => {
       vi.stubGlobal(
diff --git a/src/agents/embedded-agent-runner/openrouter-model-capabilities.ts b/src/agents/embedded-agent-runner/openrouter-model-capabilities.ts
index 8c6ea8ecb8c4..5cb8c0d93158 100644
--- a/src/agents/embedded-agent-runner/openrouter-model-capabilities.ts
+++ b/src/agents/embedded-agent-runner/openrouter-model-capabilities.ts
@@ -172,6 +172,12 @@ function parseModel(model: OpenRouterApiModel): OpenRouterModelCapabilities {
   };
 }
 
+async function cancelUnreadResponseBody(response: Response | undefined): Promise<void> {
+  if (response && !response.bodyUsed) {
+    await response.body?.cancel().catch(() => undefined);
+  }
+}
+
 // ---------------------------------------------------------------------------
 // API fetch
 // ---------------------------------------------------------------------------
@@ -179,10 +185,11 @@ function parseModel(model: OpenRouterApiModel): OpenRouterModelCapabilities {
 async function doFetch(): Promise<void> {
   const controller = new AbortController();
   const timeout = setTimeout(() => controller.abort(), FETCH_TIMEOUT_MS);
+  let response: Response | undefined;
   try {
     const fetchFn = resolveProxyFetchFromEnv() ?? globalThis.fetch;
 
-    const response = await fetchFn(OPENROUTER_MODELS_URL, {
+    response = await fetchFn(OPENROUTER_MODELS_URL, {
       signal: controller.signal,
     });
 
@@ -210,6 +217,7 @@ async function doFetch(): Promise<void> {
     log.warn(`Failed to fetch OpenRouter models: ${message}`);
   } finally {
     clearTimeout(timeout);
+    await cancelUnreadResponseBody(response);
   }
 }