fix(messages-native): answer a spent Anthropic pool as a usage limit with its reset

src/server/messages-native.ts

@@ -849,6 +849,17 @@ export async function handleNativeMessages(options: HandleNativeMessagesOptions)
   }
   releaseRetainedRequest();
 
+  // The last pool account refused on spent quota and rotation found no replacement: answer the
+  // usage limit with its reset (#6991), as the bridge lane does, not the upstream "try again later".
+  const poolUsageLimit = response.status === 429 && oauthBinding
+    ? anthropicRoutingFor(nativeInstance!).anthropicPoolUsageLimitAfterRefusal(Date.now(), oauthBinding.routeDecision, route.modelId)
+    : null;
+  if (poolUsageLimit) {
+    discard(response);
+    cleanupAbort();
+    logCtx.errorCode = "usage_limit_reached";
+    return retainUpstreamMessagesRequestId(localOAuthFailure(poolUsageLimit)!, response.headers);
+  }
   if (!response.ok) {
     let bodyText = "";
     try {

tests/claude-integration/messages-native-oauth.test.ts

@@ -819,6 +819,33 @@ test("shared quota exhaustion is bounded and never resends an already-tried alte
   expect(new Set(sent.map(entry => entry.headers.get("authorization"))).size).toBe(sent.length);
 });
 
+test("a pool whose every account refuses on spent quota answers the usage limit and its reset (#6991 parity)", async () => {
+  await seed(2);
+  const config = fixtureConfig();
+  config.anthropicAccountPool = { enabled: true };
+  const resetSeconds = Math.floor(Date.now() / 1000) + 7_200;
+  config.providers.anthropic!.fetch = (async (input, init) => {
+    sent.push({ url: String(input), headers: new Headers(init?.headers), body: JSON.parse(String(init?.body)) });
+    return Response.json({ type: "error", error: { type: "rate_limit_error", message: "fixture window spent" } }, {
+      status: 429,
+      headers: {
+        "anthropic-ratelimit-unified-7d-status": "rejected", "anthropic-ratelimit-unified-7d-reset": String(resetSeconds),
+        "retry-after": "7200", "request-id": "req_fixture_spent",
+      },
+    });
+  }) as typeof fetch;
+  const { response, text, row } = await send(config, { ...BODY, stream: false });
+  expect(response.status).toBe(429);
+  expect(sent).toHaveLength(2);
+  expect(JSON.parse(text).error).toMatchObject({
+    type: "rate_limit_error",
+    message: `All Anthropic OAuth accounts have reached their usage limit; the first one resets at ${new Date(resetSeconds * 1000).toISOString()}`,
+  });
+  expect(Number(response.headers.get("retry-after"))).toBeGreaterThan(7_000);
+  expect(response.headers.get("request-id")).toBe("req_fixture_spent");
+  expect(row.protocolTrace?.mode).toBe("native");
+});
+
 test("family lease releases when spend admission refuses without a physical send", async () => {
   await seed(1);
   const config = fixtureConfig();