fix(agents): classify account-restricted model 400s as model_not_found

ObliviateRickLin · ObliviateRickLin · commit 7abbb6fc51ab · 2026-07-12T13:15:05.000+08:00
OpenAI-backed runtimes reject plan/account-restricted models with HTTP 400 invalid_request_error ("The '<model>' model is not supported when using Codex with a ChatGPT account."). Without a model_not_found match the ambiguous-400 branch collapses this into a format failure, so users get the generic retry//new copy for a config-only problem (#104490). The 'when using' qualifier keeps capability rejections ("not supported for tool calling") out of the class, preserving the #97611 contract. Fixes #104490
diff --git a/src/agents/failover-error.test.ts b/src/agents/failover-error.test.ts
@@ -377,6 +377,35 @@ describe("failover-error", () => {
     ).toBe("model_not_found");
   });
 
+  it("classifies account-restricted model 400s as model_not_found (#104490)", () => {
+    // Codex/OpenAI reject plan-restricted models with HTTP 400
+    // invalid_request_error; without a model_not_found classification the 400
+    // branch collapses this into "format" and users get generic retry//new copy
+    // for a config-only failure.
+    const codexAccountRestrictedPayload =
+      '{"type":"error","status":400,"error":{"type":"invalid_request_error","message":"The \'gpt-5.5-pro\' model is not supported when using Codex with a ChatGPT account."}}';
+    expect(
+      resolveFailoverReasonFromError({
+        provider: "codex",
+        status: 400,
+        message: codexAccountRestrictedPayload,
+      }),
+    ).toBe("model_not_found");
+    expect(
+      resolveFailoverReasonFromError({
+        message:
+          "The 'gpt-5.5-pro' model is not supported when using Codex with a ChatGPT account.",
+      }),
+    ).toBe("model_not_found");
+    // Capability rejections stay out of the model_not_found class.
+    expect(
+      resolveFailoverReasonFromError({
+        status: 400,
+        message: "This model is not supported for tool calling.",
+      }),
+    ).not.toBe("model_not_found");
+  });
+
   it("does not classify generic access errors as model_not_found", () => {
     expect(
       resolveFailoverReasonFromError({
diff --git a/src/agents/live-model-errors.test.ts b/src/agents/live-model-errors.test.ts
@@ -41,6 +41,18 @@ describe("live model error helpers", () => {
       ),
     ).toBe(true);
     expect(isModelNotFoundErrorMessage("Not supported model some-model-id")).toBe(true);
+    // #104490: account/plan-restricted model rejections (Codex + ChatGPT
+    // account) are model-unavailable, including the raw JSON envelope shape.
+    expect(
+      isModelNotFoundErrorMessage(
+        "The 'gpt-5.5-pro' model is not supported when using Codex with a ChatGPT account.",
+      ),
+    ).toBe(true);
+    expect(
+      isModelNotFoundErrorMessage(
+        '{"type":"error","status":400,"error":{"type":"invalid_request_error","message":"The \'gpt-5.5-pro\' model is not supported when using Codex with a ChatGPT account."}}',
+      ),
+    ).toBe(true);
     expect(
       isModelNotFoundErrorMessage(
         "404 The free model has been deprecated. Transition to qwen/qwen3.6-plus for continued paid access.",
diff --git a/src/agents/live-model-errors.ts b/src/agents/live-model-errors.ts
@@ -31,6 +31,14 @@ export function isModelNotFoundErrorMessage(raw: string): boolean {
   if (/\bnot supported model\b/i.test(msg)) {
     return true;
   }
+  // OpenAI-backed runtimes reject account/plan-restricted models with
+  // "The '<model>' model is not supported when using <runtime> with <account>".
+  // The model id must change (or the account), so treat it as model-unavailable;
+  // the "when using" qualifier keeps capability errors ("not supported for
+  // tool calling") out of this class.
+  if (/\bmodel\b[^.]{0,120}?\bis not supported when using\b/i.test(msg)) {
+    return true;
+  }
   if (/model:\s*[a-z0-9._/-]+/i.test(msg) && /not(?:[_\-\s])?found/i.test(msg)) {
     return true;
   }
