### Completed (21/21)

All user stories completed!

## Summary

Tool 返回值结构化重构项目（tool-result-refactor）已全部完成：
- 21 个用户故事全部实现
- 从 US-001 (ToolResult struct) 到 US-021 (Heartbeat ExecuteHeartbeatWithTools)
- 所有验收标准均已满足
- 代码通过 typecheck 和测试验证

### User Stories Completed

- US-001: Add ToolResult struct and helper functions
- US-002: Modify Tool interface to return *ToolResult
- US-003: Modify ToolRegistry to process ToolResult
- US-004: Delete isToolConfirmationMessage function
- US-005: Update AgentLoop tool result processing logic
- US-006: Add AsyncCallback type and AsyncTool interface
- US-007: Heartbeat async task execution support
- US-008: Inject callback into async tools in AgentLoop
- US-009: State save atomicity - SetLastChannel
- US-010: Update RecordLastChannel to use atomic save
- US-011: Refactor MessageTool to use ToolResult
- US-012: Refactor ShellTool to use ToolResult
- US-013: Refactor FilesystemTool to use ToolResult
- US-014: Refactor WebTool to use ToolResult
- US-015: Refactor EditTool to use ToolResult
- US-016: Refactor CronTool to use ToolResult
- US-017: Refactor SpawnTool to use AsyncTool and callbacks
- US-018: Refactor SubagentTool to use ToolResult
- US-019: Enable heartbeat by default in config
- US-020: Move heartbeat log to memory directory
- US-021: Heartbeat calls ExecuteHeartbeatWithTools

### In Progress
None

### Blocked
None

### Pending
None