fix(failover): treat stop reason error as timeout

src/agents/failover-error.test.ts

@@ -35,7 +35,7 @@ describe("failover-error", () => {
     expect(resolveFailoverReasonFromError({ code: "ECONNRESET" })).toBe("timeout");
   });
 
-  it("infers timeout from abort stop-reason messages", () => {
+  it("infers timeout from abort/error stop-reason messages", () => {
     expect(resolveFailoverReasonFromError({ message: "Unhandled stop reason: abort" })).toBe(
       "timeout",
     );
@@ -43,7 +43,9 @@ describe("failover-error", () => {
       "timeout",
     );
     expect(resolveFailoverReasonFromError({ message: "stop reason: abort" })).toBe("timeout");
+    expect(resolveFailoverReasonFromError({ message: "stop reason: error" })).toBe("timeout");
     expect(resolveFailoverReasonFromError({ message: "reason: abort" })).toBe("timeout");
+    expect(resolveFailoverReasonFromError({ message: "reason: error" })).toBe("timeout");
   });
 
   it("treats AbortError reason=abort as timeout", () => {

src/agents/failover-error.ts

@@ -6,7 +6,7 @@ import {
 } from "./pi-embedded-helpers.js";
 
 const TIMEOUT_HINT_RE =
-  /timeout|timed out|deadline exceeded|context deadline exceeded|stop reason:\s*abort|reason:\s*abort|unhandled stop reason:\s*(?:abort|error)/i;
+  /timeout|timed out|deadline exceeded|context deadline exceeded|stop reason:\s*(?:abort|error)|reason:\s*(?:abort|error)|unhandled stop reason:\s*(?:abort|error)/i;
 const ABORT_TIMEOUT_RE = /request was aborted|request aborted/i;
 
 export class FailoverError extends Error {

src/agents/model-fallback.test.ts

@@ -751,6 +751,17 @@ describe("runWithModelFallback", () => {
     });
   });
 
+  it("falls back on abort errors with reason: error", async () => {
+    await expectFallsBackToHaiku({
+      provider: "openai",
+      model: "gpt-4.1-mini",
+      firstError: Object.assign(new Error("aborted"), {
+        name: "AbortError",
+        reason: "reason: error",
+      }),
+    });
+  });
+
   it("falls back when message says aborted but error is a timeout", async () => {
     await expectFallsBackToHaiku({
       provider: "openai",

src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts

@@ -427,7 +427,9 @@ describe("isFailoverErrorMessage", () => {
       "Unhandled stop reason: abort",
       "Unhandled stop reason: error",
       "stop reason: abort",
+      "stop reason: error",
       "reason: abort",
+      "reason: error",
     ];
     for (const sample of samples) {
       expect(isTimeoutErrorMessage(sample)).toBe(true);

src/agents/pi-embedded-helpers/errors.ts

@@ -641,8 +641,8 @@ const ERROR_PATTERNS = {
     "deadline exceeded",
     "context deadline exceeded",
     /without sending (?:any )?chunks?/i,
-    /\bstop reason:\s*abort\b/i,
-    /\breason:\s*abort\b/i,
+    /\bstop reason:\s*(?:abort|error)\b/i,
+    /\breason:\s*(?:abort|error)\b/i,
     /\bunhandled stop reason:\s*(?:abort|error)\b/i,
   ],
   billing: [