feat: add agent tool support (todo_tool)

[wgnrai]

Summary

Adds native agent tool support to the Todo List plugin, enabling Agent Zero subordinate agents (developer, researcher, hacker, etc.) to create, view, update, delete, and manage tasks programmatically.

Changes

New Files

• tools/todo_tool.py (275 lines) — TodoTool class with 9 actions:

  • create — Create tasks with title, description, status, priority, project, agent_profile, tags
  • list — List/filter tasks by project, agent, status, priority, tag, search
  • get — Get a single task by ID
  • update — Update any task field
  • delete — Delete a task (requires confirmed: true guardrail)
  • link_chat / unlink_chat — Link/unlink chat sections to tasks
  • stats — Get task statistics
  • projects — List all project names
  • Error handling on all actions, clean formatted text output

• prompts/agent.system.tool.todo_tool.md (207 lines) — Agent-facing documentation:

  • All 9 actions with parameter tables
  • Valid status/priority values
  • Non-negotiable deletion policy requiring Principal authorization
  • JSON usage examples

Key Design Decisions

1. Deletion Guardrail — Tool blocks deletions unless confirmed: true is passed. This prevents agents from accidentally deleting user tasks.
2. kwargs action fallback — The framework passes colon-syntax actions via kwargs.get("action"), not self.method. The tool checks both for compatibility. This pattern matches core tools (scheduler.py, skills_tool.py).
3. Purely additive — No changes to existing helpers, API, or WebUI code. All existing functionality preserved.

Testing

• Swap tested against live Agent Zero instance
• Subordinate agents successfully created and listed tasks via todo_tool:create and todo_tool:list
• Deletion guardrail verified — blocks without confirmed: true

Compatibility

• Agent Zero v0.8+
• Python 3.11+
• No new dependencies