diff --git a/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts b/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts
index eb16f20d49a..dabe78c2d26 100644
--- a/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts
+++ b/src/agents/pi-embedded-helpers.isbillingerrormessage.test.ts
@@ -656,6 +656,18 @@ describe("isFailoverErrorMessage", () => {
     ]);
   });
 
+  it("matches AbortError / stream-abort messages as timeout (#58315)", () => {
+    expectTimeoutFailoverSamples([
+      "The operation was aborted",
+      "This operation was aborted",
+      "the operation was aborted",
+      "stream closed",
+      "stream was closed",
+      "stream aborted",
+      "stream was aborted",
+    ]);
+  });
+
   it("matches Gemini MALFORMED_RESPONSE stop reason as timeout (#42149)", () => {
     expectTimeoutFailoverSamples([
       "Unhandled stop reason: MALFORMED_RESPONSE",
diff --git a/src/agents/pi-embedded-helpers/failover-matches.ts b/src/agents/pi-embedded-helpers/failover-matches.ts
index 405a31a81e8..1b3cb262e15 100644
--- a/src/agents/pi-embedded-helpers/failover-matches.ts
+++ b/src/agents/pi-embedded-helpers/failover-matches.ts
@@ -63,6 +63,11 @@ 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,
+    // AbortError messages from fetch/stream aborts (Ollama NDJSON stream
+    // timeouts, signal aborts, etc.) — without these the flattened message
+    // falls through to reason=unknown (#58315).
+    /\boperation was aborted\b/i,
+    /\bstream (?:was )?(?:closed|aborted)\b/i,
   ],
   billing: [
     /["']?(?:status|code)["']?\s*[:=]\s*402\b|\bhttp\s*402\b|\berror(?:\s+code)?\s*[:=]?\s*402\b|\b(?:got|returned|received)\s+(?:a\s+)?402\b|^\s*402\s+payment/i,