fix(gsd): treat queued-user-message skip as non-retryable interruption

Add isQueuedUserMessageSkip() predicate and extend recordToolInvocationError
to catch "Skipped due to queued user message." so auto-mode pauses instead
of retrying the same unit until the provider aborts with 3 consecutive
validation failures.

Fixes #3595

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/resources/extensions/gsd/auto-tool-tracking.ts

@@ -102,3 +102,13 @@ export function isToolInvocationError(errorMsg: string): boolean {
   if (!errorMsg) return false;
   return TOOL_INVOCATION_ERROR_RE.test(errorMsg);
 }
+
+/**
+ * Returns true if the error message indicates the tool was skipped because
+ * a queued user message interrupted the turn (#3595).  Retrying will produce
+ * the same skip, so the unit should be paused rather than retried.
+ */
+export function isQueuedUserMessageSkip(errorMsg: string): boolean {
+  if (!errorMsg) return false;
+  return /^Skipped due to queued user message\.?$/i.test(errorMsg.trim());
+}

src/resources/extensions/gsd/auto.ts

@@ -76,6 +76,7 @@ import {
   hasInteractiveToolInFlight,
   clearInFlightTools,
   isToolInvocationError,
+  isQueuedUserMessageSkip,
 } from "./auto-tool-tracking.js";
 import { closeoutUnit } from "./auto-unit-closeout.js";
 import { recoverTimedOutUnit } from "./auto-timeout-recovery.js";
@@ -397,7 +398,7 @@ export function markToolEnd(toolCallId: string): void {
  */
 export function recordToolInvocationError(toolName: string, errorMsg: string): void {
   if (!s.active) return;
-  if (isToolInvocationError(errorMsg)) {
+  if (isToolInvocationError(errorMsg) || isQueuedUserMessageSkip(errorMsg)) {
     s.lastToolInvocationError = `${toolName}: ${errorMsg}`;
   }
 }

src/resources/extensions/gsd/tests/tool-invocation-error-loop-break.test.ts

@@ -44,7 +44,7 @@ describe("#2883: tool invocation error tracking on AutoSession", () => {
 
 // ─── isToolInvocationError classifier ────────────────────────────────────
 
-import { isToolInvocationError } from "../auto-tool-tracking.ts";
+import { isToolInvocationError, isQueuedUserMessageSkip } from "../auto-tool-tracking.ts";
 
 describe("#2883: isToolInvocationError classification", () => {
   test("detects JSON validation failure pattern", () => {
@@ -101,3 +101,31 @@ describe("#2883: isToolInvocationError classification", () => {
     assert.equal(isToolInvocationError("ECONNRESET"), false);
   });
 });
+
+// ─── isQueuedUserMessageSkip classifier (#3595) ─────────────────────────
+
+describe("#3595: isQueuedUserMessageSkip classification", () => {
+  test("detects exact skip message with period", () => {
+    assert.equal(isQueuedUserMessageSkip("Skipped due to queued user message."), true);
+  });
+
+  test("detects skip message without period", () => {
+    assert.equal(isQueuedUserMessageSkip("Skipped due to queued user message"), true);
+  });
+
+  test("detects skip message with surrounding whitespace", () => {
+    assert.equal(isQueuedUserMessageSkip("  Skipped due to queued user message.  "), true);
+  });
+
+  test("returns false for normal tool errors", () => {
+    assert.equal(isQueuedUserMessageSkip("Slice S01 is already complete"), false);
+  });
+
+  test("returns false for empty string", () => {
+    assert.equal(isQueuedUserMessageSkip(""), false);
+  });
+
+  test("returns false for partial match (substring)", () => {
+    assert.equal(isQueuedUserMessageSkip("Error: Skipped due to queued user message. Retry later."), false);
+  });
+});