fix(acpx): record turn activity at the moment a stop fires

Sandbox claude_local runs that hit the 4h wall-clock backstop report
acpLastEventAgeMs at finalization, after the timeout's cancel. Some agents
emit closing events on cancel, so a turn that went silent minutes into the
run can look active at its deadline.

Record, for a stopped turn, the last-event age and the oldest pending
tool's age as of the stop, plus the pending tools' closed ACP ToolKind
labels. The server forwards these to run-failure diagnostics only when
they are non-negative integers or closed enum labels.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/src/services/__tests__/run-failure-diagnostics.test.ts

@@ -323,11 +323,29 @@ describe("run failure diagnostics", () => {
     expect(JSON.stringify(result)).not.toContain("private");
   });
 
+  it("includes stop-time ACP activity and closed pending tool-kind labels", () => {
+    const result = sanitizeRunFailureDiagnostics(collectRunFailureDiagnostics(run({ resultJson: {
+      acpLastEventAgeMs: 700, acpLastEventAgeAtStopMs: 14_000_000, acpOldestPendingToolAgeAtStopMs: 14_100_000,
+      acpPendingToolKinds: "execute,unknown",
+    } }), {}));
+    expect(result.execution).toEqual({
+      acpLastEventAgeMs: 700, acpLastEventAgeAtStopMs: 14_000_000, acpOldestPendingToolAgeAtStopMs: 14_100_000,
+      acpPendingToolKinds: "execute,unknown",
+    });
+  });
+
+  it.each(["execute,private command", "", "execute,", "Execute", ["execute"], 1])(
+    "omits pending tool kinds that are not closed labels (%j)", (value) => {
+      const result = collectRunFailureDiagnostics(run({ resultJson: { acpPendingToolKinds: value } }), {});
+      expect(result.execution).toEqual({});
+    },
+  );
+
   it.each([null, -1, Infinity, NaN, 1.5, Number.MAX_SAFE_INTEGER + 1, "private", {}])(
     "omits invalid ACP activity fields (%j)", (value) => {
       const result = collectRunFailureDiagnostics(run({ resultJson: {
         acpLastEventAgeMs: value, acpObservedEventCount: value, acpPendingToolCount: value,
-        acpToolInventoryComplete: value,
+        acpToolInventoryComplete: value, acpLastEventAgeAtStopMs: value, acpOldestPendingToolAgeAtStopMs: value,
       } }), {});
       expect(result.execution).toEqual({});
     },

server/src/services/run-failure-diagnostics.ts

@@ -6,6 +6,7 @@ import { readProcessLossDiagnostic } from "./process-loss-diagnostics.js";
 import { WORKSPACE_RESTORE_FAILURE_CODES } from "@paperclipai/shared";
 import { redactDiagnosticText } from "@paperclipai/adapter-utils/command-redaction";
 import { sanitizeWorkspaceRestoreDiagnostic } from "@paperclipai/adapter-utils/workspace-restore-diagnostics";
+import { ACP_TOOL_KINDS } from "@paperclipai/adapter-utils/acpx-engine/constants";
 import { redactCurrentUserText } from "../log-redaction.js";
 import { redactSensitiveText, REDACTED_EVENT_VALUE } from "../redaction.js";
 import { readNativeModelRejectionDiagnostic } from "./native-runtime/native-provider-failure.js";
@@ -41,6 +42,15 @@ export interface RunFailureDiagnostics {
   truncatedFields: string[];
 }
 
+const ACP_PENDING_TOOL_KIND_LABELS: ReadonlySet<string> = new Set([...ACP_TOOL_KINDS, "unknown"]);
+
+/** Closed ACP tool-kind labels only; any other content drops the whole field. */
+function readAcpPendingToolKinds(value: unknown): string | null {
+  if (typeof value !== "string" || value.length === 0 || value.length > 200) return null;
+  const kinds = value.split(",");
+  return kinds.every((kind) => ACP_PENDING_TOOL_KIND_LABELS.has(kind)) ? value : null;
+}
+
 function read(value: unknown, key: string): unknown {
   if (!value || typeof value !== "object") return undefined;
   try {
@@ -197,10 +207,15 @@ export function collectRunFailureDiagnostics(run: Run, options: RunFailureReport
     "mode", "stopReason", "timeoutFired", "timeoutSource", "timeoutConfigured",
     "effectiveTimeoutSec", "errorFamily",
   ]));
-  for (const field of ["acpLastEventAgeMs", "acpObservedEventCount", "acpPendingToolCount"]) {
+  for (const field of [
+    "acpLastEventAgeMs", "acpObservedEventCount", "acpPendingToolCount",
+    "acpLastEventAgeAtStopMs", "acpOldestPendingToolAgeAtStopMs",
+  ]) {
     const value = read(result, field);
     if (typeof value === "number" && Number.isSafeInteger(value) && value >= 0) execution[field] = value;
   }
+  const pendingToolKinds = readAcpPendingToolKinds(read(result, "acpPendingToolKinds"));
+  if (pendingToolKinds) execution.acpPendingToolKinds = pendingToolKinds;
   const toolInventoryComplete = read(result, "acpToolInventoryComplete");
   if (typeof toolInventoryComplete === "boolean") execution.acpToolInventoryComplete = toolInventoryComplete;
   const restoreFailure = read(result, "workspaceRestoreFailure");