fix(agent): 自动压缩死循环修复 — keepTail 预算化 + 摘要执行可靠性

Cursor++/src/server/config/paths.ts

@@ -53,6 +53,22 @@ export function getLogsDir(): string {
   return join(getCcursorDir(), 'logs')
 }
 
+/**
+ * 工具输出溢出落盘目录 ~/.ccursor/spill。
+ *
+ * 入口截断 (Task 报告 ENTRY_CAP) 在截断前把全文写入
+ *   ~/.ccursor/spill/<conversationId>/<toolCallId>.txt
+ * 截断标注携带该路径 —— 满足"被截断内容可恢复"约束 (设计文档 §3.2 审计修正)。
+ */
+export function getSpillDir(): string {
+  return join(getCcursorDir(), 'spill')
+}
+
+/** 单会话 spill 子目录: ~/.ccursor/spill/<conversationId> */
+export function getConversationSpillDir(conversationId: string): string {
+  return join(getSpillDir(), conversationId)
+}
+
 /**
  * 每窗口一个独立日志文件, 避免多实例并发写冲突。
  *   windowId 来自 VSCODE_PROCESS_TITLE 中的 [N-M],

Cursor++/src/server/handlers/agent/checkpointManager.ts

@@ -37,6 +37,7 @@ export function emitRollingCheckpoint(params: {
 
     logger.info({
         conversationId: params.conversationId,
+        origin: 'rolling',
         round: params.round,
         nextBlobbedMessageIndex: params.nextBlobbedMessageIndex,
         rollingTokenDetails,
@@ -103,6 +104,7 @@ export function emitFinalCheckpoint(params: {
 
     logger.info({
         conversationId: params.conversationId,
+        origin: 'final',
         blocks: params.lastAssistantContent?.length ?? 0,
         types: params.lastAssistantContent?.map(b => b.type) ?? [],
         thinkingLen: assistantSummary.thinking?.length ?? 0,

Cursor++/src/server/handlers/agent/compactionLock.ts

@@ -0,0 +1,76 @@
+/**
+ * 会话级压缩互斥锁 (设计文档 §7#7, 2026-08-29 审计修正升级为本阶段实施)
+ *
+ * 动机: inline 自动压缩与 summarizeAction 手动压缩并发时, 后写者可能用
+ * 较旧的历史覆盖更新状态 (数据丢失, 严重性高于"无害只浪费")。
+ * 两路同进程 → in-process 锁即可; checkpoint 版本 CAS + 压缩操作幂等 ID 留 future work。
+ *
+ * 语义:
+ *   - inline 路径用 tryAcquire: 锁被占则本轮跳过 (计数观测, 下轮重试)
+ *   - summarizeAction 路径用 waitForRelease: 等待持锁者完成后再重新评估
+ */
+
+interface CompactionLockEntry {
+    held: boolean;
+    waiters: Array<() => void>;
+}
+
+const compactionLocks = new Map<string, CompactionLockEntry>();
+
+/** 争用计数 (观测: 互斥锁的等待/跳过次数, [AUTOCOMPACT] 日志消费) */
+const contentionCounts = new Map<string, number>();
+
+function getOrCreateLock(conversationId: string): CompactionLockEntry {
+    let entry = compactionLocks.get(conversationId);
+    if (!entry) {
+        entry = { held: false, waiters: [] };
+        compactionLocks.set(conversationId, entry);
+    }
+    return entry;
+}
+
+/** 尝试获取; 已被占则计数并返回 false (inline 路径: 跳过本轮) */
+export function tryAcquireCompactionLock(conversationId: string): boolean {
+    const entry = getOrCreateLock(conversationId);
+    if (entry.held) {
+        contentionCounts.set(conversationId, (contentionCounts.get(conversationId) ?? 0) + 1);
+        return false;
+    }
+    entry.held = true;
+    return true;
+}
+
+/** 等待锁释放 (不获取 — summarizeAction 释放后重新评估是否仍需压缩) */
+export function waitForCompactionLockRelease(conversationId: string): Promise<void> {
+    const entry = getOrCreateLock(conversationId);
+    if (!entry.held)
+        return Promise.resolve();
+    contentionCounts.set(conversationId, (contentionCounts.get(conversationId) ?? 0) + 1);
+    return new Promise((resolve) => {
+        entry.waiters.push(resolve);
+    });
+}
+
+/** 释放; 唤醒全部等待者 (等待者自行重评估, 不自动传递锁) */
+export function releaseCompactionLock(conversationId: string): void {
+    const entry = compactionLocks.get(conversationId);
+    if (!entry)
+        return;
+    entry.held = false;
+    const waiters = [...entry.waiters];
+    entry.waiters = [];
+    for (const waiter of waiters)
+        waiter();
+    if (!entry.held && entry.waiters.length === 0)
+        compactionLocks.delete(conversationId);
+}
+
+/** 当前会话的争用计数 (观测日志用) */
+export function getCompactionContentionCount(conversationId: string): number {
+    return contentionCounts.get(conversationId) ?? 0;
+}
+
+/** 只读探测 (不计争用): 错误驱动重试路径的等待循环用 */
+export function isCompactionLockHeld(conversationId: string): boolean {
+    return compactionLocks.get(conversationId)?.held === true;
+}