From 790a17ac3395d4cdfd07e2a4adcb0cb05e163171 Mon Sep 17 00:00:00 2001
From: diegosouzapw <diegosouzapw@users.noreply.github.com>
Date: Fri, 7 Aug 2026 10:47:57 -0300
Subject: [PATCH] fix(errorClassifier): classify ChatGPT Web SENTINEL_BLOCKED
 403 as FORBIDDEN, enabling combo fallback (#8813)

---
 changelog.d/fixes/8813-chatgpt-sentinel.md    |  1 +
 open-sse/services/errorClassifier.ts          | 14 ++++++++++
 .../errorClassifier-noauth-403-6315.test.ts   | 27 +++++++++++++++++++
 3 files changed, 42 insertions(+)
 create mode 100644 changelog.d/fixes/8813-chatgpt-sentinel.md

diff --git a/changelog.d/fixes/8813-chatgpt-sentinel.md b/changelog.d/fixes/8813-chatgpt-sentinel.md
new file mode 100644
index 0000000000..0cd1091c5e
--- /dev/null
+++ b/changelog.d/fixes/8813-chatgpt-sentinel.md
@@ -0,0 +1 @@
+- fix(errorClassifier): classify ChatGPT Web SENTINEL_BLOCKED 403 as terminal FORBIDDEN, enabling proper combo fallback (#8813)
diff --git a/open-sse/services/errorClassifier.ts b/open-sse/services/errorClassifier.ts
index 7f1ff1dece..71bc81f5eb 100644
--- a/open-sse/services/errorClassifier.ts
+++ b/open-sse/services/errorClassifier.ts
@@ -245,6 +245,20 @@ export function classifyProviderError(
     if (recoverableProject403) {
       return PROVIDER_ERROR_TYPES.PROJECT_ROUTE_ERROR;
     }
+    // #8813 — ChatGPT Web's Cloudflare Sentinel/Turnstile 403 is a TERMINAL
+    // block: the user's IP/session needs a browser Turnstile challenge, and
+    // retrying the same connection will keep 403ing. Classify as FORBIDDEN so
+    // the connection gets banned and combo routing falls back to other providers.
+    // Must be checked BEFORE the generic apikey-403→null return below, which
+    // is designed for normal API-key auth 403s that ARE recoverable.
+    if (
+      bodyStr.includes("SENTINEL_BLOCKED") ||
+      /\bSentinel\b[^\n]{0,80}\bblocked\b/i.test(bodyStr) ||
+      /\bTurnstile required\b/i.test(bodyStr)
+    ) {
+      return PROVIDER_ERROR_TYPES.FORBIDDEN;
+    }
+
     if (provider && getProviderCategory(provider) === "apikey") {
       return null;
     }
diff --git a/tests/unit/errorClassifier-noauth-403-6315.test.ts b/tests/unit/errorClassifier-noauth-403-6315.test.ts
index 1c9ede34f7..6d02d8c1a7 100644
--- a/tests/unit/errorClassifier-noauth-403-6315.test.ts
+++ b/tests/unit/errorClassifier-noauth-403-6315.test.ts
@@ -26,6 +26,33 @@ test("control: apikey-provider bare 403 still recoverable (null) — no regressi
   assert.equal(classifyProviderError(403, "forbidden", "openai"), null);
 });
 
+test("#8813: chatgpt-web SENTINEL_BLOCKED 403 with 'Sentinel/Turnstile required' → FORBIDDEN (terminal)", () => {
+  // The executor returns error code "SENTINEL_BLOCKED" in the JSON body.
+  // This is a TERMINAL state — retrying the same blocked session will keep 403ing.
+  // Must be classified as FORBIDDEN so the circuit breaker marks the connection
+  // as banned and combo routing falls back to other providers.
+  const body = JSON.stringify({
+    error: {
+      message:
+        "ChatGPT blocked the request (Sentinel/Turnstile required). Try again later or open chatgpt.com in a browser to refresh state.",
+      type: "upstream_error",
+      code: "SENTINEL_BLOCKED",
+    },
+  });
+  assert.equal(
+    classifyProviderError(403, body, "chatgpt-web"),
+    PROVIDER_ERROR_TYPES.FORBIDDEN
+  );
+});
+
+test("#8813: chatgpt-web SENTINEL_BLOCKED 403 with raw 'Sentinel blocked' text → FORBIDDEN (terminal)", () => {
+  // Edge case: when the raw text includes "Sentinel" and 403, classify as terminal.
+  assert.equal(
+    classifyProviderError(403, "Sentinel blocked the request", "chatgpt-web"),
+    PROVIDER_ERROR_TYPES.FORBIDDEN
+  );
+});
+
 test("control: recognized ban phrase on a no-credential provider still terminal (ACCOUNT_DEACTIVATED)", () => {
   const body = "This service has been disabled in this account for violation of policy.";
   assert.equal(classifyProviderError(403, body, "mimocode"), PROVIDER_ERROR_TYPES.ACCOUNT_DEACTIVATED);