From 30b226c44e081638f79ee09ba9a0212698a587e6 Mon Sep 17 00:00:00 2001
From: Xiangzhe <bakryun0718@proton.me>
Date: Thu, 13 Aug 2026 16:24:28 -0300
Subject: [PATCH] feat(sse): restate agentrouter quota 403/400 to 429 before
 classification

---
 open-sse/handlers/chatCore.ts                 | 22 +++++++++++++++++++
 .../unit/upstream-status-restatement.test.ts  | 17 ++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/open-sse/handlers/chatCore.ts b/open-sse/handlers/chatCore.ts
index d762d8bd2d..eb0d5b587b 100644
--- a/open-sse/handlers/chatCore.ts
+++ b/open-sse/handlers/chatCore.ts
@@ -184,6 +184,7 @@ import {
   DEFAULT_MAX_TOKENS,
   STREAM_DISCONNECT_GRACE_PERIOD_MS,
 } from "../config/constants.ts";
+import { applyStatusRestatement } from "../config/upstreamStatusRestatement.ts";
 import { createRecoverableStream, makeContinuationBody } from "../services/streamRecovery.ts";
 import {
   resolveResilienceSettings,
@@ -3650,6 +3651,27 @@ export async function handleChatCore({
       upstreamErrorType = details.errorType as string | undefined;
     }
 
+    // Gateways like agentrouter misstate temporary quota exhaustion as 403/400,
+    // which downstream classification treats as AUTH_ERROR and clients like
+    // Claude Code treat as permanent. Restate to 429 (+ synthetic Retry-After)
+    // BEFORE any classification so both the fallback engine and the surfaced
+    // client status see a retryable error. Registry-scoped per provider.
+    const restatement = applyStatusRestatement({
+      provider,
+      status: statusCode,
+      message,
+      body: upstreamErrorBody,
+      retryAfterMs,
+    });
+    if (restatement.ruleId) {
+      statusCode = restatement.status;
+      retryAfterMs = restatement.retryAfterMs;
+      log?.info?.(
+        "STATUS_RESTATE",
+        `${provider} ${restatement.fromStatus}→${statusCode} (${restatement.ruleId})`
+      );
+    }
+
     const signatureRecovery = await recoverAnthropicThinkingSignature({
       provider,
       statusCode,
diff --git a/tests/unit/upstream-status-restatement.test.ts b/tests/unit/upstream-status-restatement.test.ts
index 8d1c6c829b..7c59bc8b15 100644
--- a/tests/unit/upstream-status-restatement.test.ts
+++ b/tests/unit/upstream-status-restatement.test.ts
@@ -107,3 +107,20 @@ test("R9: registry exposes agentrouter so future gateways copy the one-line reci
   const rules = statusRestatementRegistry.get("agentrouter");
   assert.ok(rules && rules.length > 0);
 });
+
+test("R10: chatCore wires applyStatusRestatement into the providerFailure block", async () => {
+  // chatCore is a god-file that cannot be imported standalone in unit tests
+  // (side-effectful DB/env wiring), so the wiring contract is asserted at the
+  // source level: the hook must exist, run against the parsed error, and
+  // reassign both statusCode and retryAfterMs BEFORE classification.
+  const { readFile } = await import("node:fs/promises");
+  const src = await readFile(
+    new URL("../../open-sse/handlers/chatCore.ts", import.meta.url),
+    "utf8"
+  );
+  assert.match(src, /applyStatusRestatement\(/, "chatCore must call applyStatusRestatement");
+  const hookIndex = src.indexOf("applyStatusRestatement(");
+  const classifyIndex = src.indexOf("classifyProviderError(statusCode");
+  assert.ok(hookIndex > -1 && classifyIndex > -1 && hookIndex < classifyIndex,
+    "restatement must run BEFORE classifyProviderError so fallback sees the corrected status");
+});