fix(cursor): an aborted Cursor SDK stall no longer stops the server

packages/provider-cursor/src/server/CursorSdk.test.ts

@@ -37,6 +37,22 @@ describe("CursorSdk unhandled rejection guard", () => {
     }),
   );
 
+  it.effect("keeps the server running when the SDK aborts a stalled request", () =>
+    Effect.gen(function* () {
+      const stall = new DOMException("This operation was aborted", "AbortError");
+      stall.stack = "AbortError: This operation was aborted\n    at Is.onStall (689.js:1:111536)";
+      assert.deepStrictEqual(yield* rejectThroughGuard(stall), []);
+    }),
+  );
+
+  it.effect("still exits on an abort that did not come from the stall detector", () =>
+    Effect.gen(function* () {
+      const abort = new DOMException("This operation was aborted", "AbortError");
+      abort.stack = "AbortError: This operation was aborted\n    at somewhereElse (app.js:1:1)";
+      assert.deepStrictEqual(yield* rejectThroughGuard(abort), [[1]]);
+    }),
+  );
+
   it.effect("still exits on other rejections", () =>
     Effect.gen(function* () {
       assert.deepStrictEqual(yield* rejectThroughGuard(new Error("WritableIterable is closed")), [

packages/provider-cursor/src/server/CursorSdk.ts

@@ -43,6 +43,20 @@ function isCursorClosedStreamWrite(reason: unknown): boolean {
   return reason instanceof Error && reason.name === "WriteIterableClosedError";
 }
 
+/**
+ * When the SDK's stall detector fires it aborts the request, then rejects a promise
+ * nothing awaits. The abort is the SDK's own recovery, so it must not stop the server.
+ * Only an abort raised from `onStall` counts; any other AbortError is still unexpected.
+ */
+function isCursorStallAbort(reason: unknown): boolean {
+  return (
+    reason instanceof Error &&
+    reason.name === "AbortError" &&
+    typeof reason.stack === "string" &&
+    /\bonStall\b/.test(reason.stack)
+  );
+}
+
 function onUnhandledRejection(reason: unknown): void {
   if (isCursorShellSpawnFailure(reason)) {
     console.error("Cursor shell spawn failed. The server will keep running.", reason);
@@ -52,6 +66,10 @@ function onUnhandledRejection(reason: unknown): void {
     console.error("Cursor SDK wrote to a closed exec stream. The server will keep running.");
     return;
   }
+  if (isCursorStallAbort(reason)) {
+    console.error("Cursor SDK aborted a stalled request. The server will keep running.");
+    return;
+  }
   if (process.listenerCount("unhandledRejection") > 1) {
     return;
   }