Map fatal Codex stderr to runtime errors

apps/server/src/provider/Layers/CodexAdapter.test.ts

@@ -508,6 +508,42 @@ lifecycleLayer("CodexAdapterLive lifecycle", (it) => {
     }),
   );
 
+  it.effect("maps fatal websocket stderr notifications to runtime.error", () =>
+    Effect.gen(function* () {
+      const adapter = yield* CodexAdapter;
+      const firstEventFiber = yield* Stream.runHead(adapter.streamEvents).pipe(Effect.forkChild);
+
+      lifecycleManager.emit("event", {
+        id: asEventId("evt-process-stderr-websocket"),
+        kind: "notification",
+        provider: "codex",
+        threadId: asThreadId("thread-1"),
+        createdAt: new Date().toISOString(),
+        method: "process/stderr",
+        turnId: asTurnId("turn-1"),
+        message:
+          "2026-03-31T18:14:06.833399Z ERROR codex_api::endpoint::responses_websocket: failed to connect to websocket: HTTP error: 503 Service Unavailable, url: wss://chatgpt.com/backend-api/codex/responses",
+      } satisfies ProviderEvent);
+
+      const firstEvent = yield* Fiber.join(firstEventFiber);
+
+      assert.equal(firstEvent._tag, "Some");
+      if (firstEvent._tag !== "Some") {
+        return;
+      }
+      assert.equal(firstEvent.value.type, "runtime.error");
+      if (firstEvent.value.type !== "runtime.error") {
+        return;
+      }
+      assert.equal(firstEvent.value.turnId, "turn-1");
+      assert.equal(firstEvent.value.payload.class, "provider_error");
+      assert.equal(
+        firstEvent.value.payload.message,
+        "2026-03-31T18:14:06.833399Z ERROR codex_api::endpoint::responses_websocket: failed to connect to websocket: HTTP error: 503 Service Unavailable, url: wss://chatgpt.com/backend-api/codex/responses",
+      );
+    }),
+  );
+
   it.effect("preserves request type when mapping serverRequest/resolved", () =>
     Effect.gen(function* () {
       const adapter = yield* CodexAdapter;

apps/server/src/provider/Layers/CodexAdapter.ts

@@ -112,6 +112,13 @@ function asNumber(value: unknown): number | undefined {
   return typeof value === "number" && Number.isFinite(value) ? value : undefined;
 }
 
+const FATAL_CODEX_STDERR_SNIPPETS = ["failed to connect to websocket"];
+
+function isFatalCodexProcessStderrMessage(message: string): boolean {
+  const normalized = message.toLowerCase();
+  return FATAL_CODEX_STDERR_SNIPPETS.some((snippet) => normalized.includes(snippet));
+}
+
 function normalizeCodexTokenUsage(value: unknown): ThreadTokenUsageSnapshot | undefined {
   const usage = asObject(value);
   const totalUsage = asObject(usage?.total_token_usage ?? usage?.total);
@@ -1269,15 +1276,27 @@ function mapToRuntimeEvents(
   }
 
   if (event.method === "process/stderr") {
+    const message = event.message ?? "Codex process stderr";
+    const isFatal = isFatalCodexProcessStderrMessage(message);
     return [
-      {
-        type: "runtime.warning",
-        ...runtimeEventBase(event, canonicalThreadId),
-        payload: {
-          message: event.message ?? "Codex process stderr",
-          ...(event.payload !== undefined ? { detail: event.payload } : {}),
-        },
-      },
+      isFatal
+        ? {
+            type: "runtime.error",
+            ...runtimeEventBase(event, canonicalThreadId),
+            payload: {
+              message,
+              class: "provider_error" as const,
+              ...(event.payload !== undefined ? { detail: event.payload } : {}),
+            },
+          }
+        : {
+            type: "runtime.warning",
+            ...runtimeEventBase(event, canonicalThreadId),
+            payload: {
+              message,
+              ...(event.payload !== undefined ? { detail: event.payload } : {}),
+            },
+          },
     ];
   }