From de980c7b97fd068b45e65efc86bd247ae52a796c Mon Sep 17 00:00:00 2001
From: chaoliang yan <z5643222@ad.unsw.edu.au>
Date: Mon, 6 Apr 2026 18:56:08 +1000
Subject: [PATCH] fix(failover): classify finish_reason: network_error as
 timeout (#61281)

OpenAI-compatible providers (e.g. Z.AI) surface transport errors as
`finish_reason: network_error` in the stream body. The existing
`\breason:` pattern does not match `finish_reason:` because `_` is a
word character, so no word boundary exists before `reason`. This causes
the error to fall through unclassified and skip the timeout-failover
path entirely.

Add an explicit `\bfinish_reason:` pattern that covers the same set of
terminal reasons already handled by the `\breason:` pattern.
---
 .../pi-embedded-helpers.isbillingerrormessage.test.ts | 11 +++++++++++
 src/agents/pi-embedded-helpers/failover-matches.ts    |  5 +++++
 2 files changed, 16 insertions(+)

diff --git a/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts b/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts
index 2f478af3b6d..1ced537f30d 100644
--- a/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts
+++ b/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts
@@ -779,6 +779,17 @@ describe("isFailoverErrorMessage", () => {
     ]);
   });
 
+  it("matches Provider finish_reason: network_error as timeout (#61281)", () => {
+    // OpenAI-compatible providers like Z.AI emit this exact format.
+    // `\breason:` does not match `finish_reason:` because `_` is a word
+    // character and there is no word boundary before `reason`.
+    expectTimeoutFailoverSamples([
+      "Provider finish_reason: network_error",
+      "Provider finish_reason: abort",
+      "Provider finish_reason: malformed_response",
+    ]);
+  });
+
   it("does not classify MALFORMED_FUNCTION_CALL as timeout", () => {
     const sample = "Unhandled stop reason: MALFORMED_FUNCTION_CALL";
     expect(isTimeoutErrorMessage(sample)).toBe(false);
diff --git a/src/agents/pi-embedded-helpers/failover-matches.ts b/src/agents/pi-embedded-helpers/failover-matches.ts
index f6b7a5ed239..9934075523a 100644
--- a/src/agents/pi-embedded-helpers/failover-matches.ts
+++ b/src/agents/pi-embedded-helpers/failover-matches.ts
@@ -114,6 +114,11 @@ const ERROR_PATTERNS = {
     /\bstop reason:\s*(?:abort|error|malformed_response|network_error)\b/i,
     /\breason:\s*(?:abort|error|malformed_response|network_error)\b/i,
     /\bunhandled stop reason:\s*(?:abort|error|malformed_response|network_error)\b/i,
+    // OpenAI-compatible providers (e.g. Z.AI) surface transport-level errors as
+    // `finish_reason: network_error` in the stream body. The `\breason:` pattern
+    // above does NOT match `finish_reason:` because `_` is a word character so
+    // there is no word boundary before `reason` in `finish_reason` (#61281).
+    /\bfinish_reason:\s*(?:abort|error|malformed_response|network_error)\b/i,
     // AbortError messages from fetch/stream aborts (Ollama NDJSON stream
     // timeouts, signal aborts, etc.) — without these the flattened message
     // falls through to reason=unknown (#58315).