# Todo 10 Tool Registry Management Plan

**Status:** done

## Result

Implemented by subagent and committed as `43b0cc8 feat: add tool registry management`.

Main-session verification:

```bash
uv run pytest tests/test_event_agent.py tests/test_debug_runtime.py tests/test_websocket_api.py
uv run pytest
```

Results:

- focused EventAgent/runtime/WebSocket tests: `20 passed, 1 warning in 0.26s`
- full suite: `23 passed, 1 warning in 0.27s`

## Goal

Replace the single hardcoded EventAgent tool checkbox with a backend tool registry and UI-managed loaded tools.

## Why

The original requirement says the debug page must manage which tools are loaded in EventAgent. The MVP has only one hardcoded `handoff_note` checkbox and duplicated tool schema logic in runtime. This todo makes tools a backend-owned registry so UI and runtime share the same source of truth.

## Scope

This todo covers:

- A backend registry for available EventAgent tools.
- An API endpoint that lists available tools and their schema/description.
- Runtime tool schema lookup through the registry.
- EventAgent execution through registered handlers.
- Static UI rendering tool checkboxes from the API.
- Tests for listing tools, selected-tool behavior, and UI request payload.

This todo does not cover:

- User-authored Python tool plugins.
- Persistent tool configuration.
- Hot-reloading tools from files.
- Adding tools beyond the existing `handoff_note`.

## Files

- Create: `src/agent_lab/application/tools.py`
- Modify: `src/agent_lab/application/event_agent.py`
- Modify: `src/agent_lab/application/runtime.py`
- Modify: `src/agent_lab/presentation/web.py`
- Modify: `src/agent_lab/presentation/static/index.html`
- Modify: `src/agent_lab/presentation/static/app.js`
- Modify/add tests in `tests/test_event_agent.py`, `tests/test_debug_runtime.py`, and `tests/test_websocket_api.py`.
- Do not modify: `docs/plans/todos.md`.

## Design

Create a small registry in application layer:

- `ToolDefinition`: name, description, parameters, handler.
- `ToolRegistry.available_tools()`: returns serializable public tool metadata.
- `ToolRegistry.chat_tools(enabled_names)`: returns OpenAI-compatible tool definitions for selected names.
- `ToolRegistry.handle(event)`: executes a registered tool and returns payload dict.

`handoff_note` remains the only registered MVP tool. Unknown or disabled tools should still produce tool replies with explicit JSON errors, preserving current runtime behavior.

`DebugRuntime` should accept an optional registry, defaulting to the built-in registry. `EventAgent` should also receive that registry. The runtime should stop building tool schemas manually.

`GET /api/tools` returns:

```json
[
  {
    "name": "handoff_note",
    "description": "Send a note to the event agent.",
    "parameters": { "type": "object", "properties": { "message": { "type": "string" } }, "required": ["message"] }
  }
]
```

The static UI should fetch `/api/tools` on load, render a checkbox per tool, and send selected names in `event_agent.enabled_tools`.

## Steps

1. Add failing tests for:
   - `GET /api/tools` returns `handoff_note` metadata.
   - Runtime passes selected tool schemas from registry into ChatAgent.
   - EventAgent returns disabled/unknown errors through the registry path.
   - Static HTML/JS no longer hardcodes a `tool-handoff-note` checkbox dependency.
2. Implement `application/tools.py`.
3. Refactor `EventAgent` and `DebugRuntime` to use `ToolRegistry`.
4. Add `GET /api/tools`.
5. Update static UI to render tool checkboxes dynamically and preserve default checked state.
6. Run:

```bash
uv run pytest tests/test_event_agent.py tests/test_debug_runtime.py tests/test_websocket_api.py
uv run pytest
```

## Verification

Expected result:

- Tool metadata comes from backend API.
- Runtime and EventAgent use the same registry.
- UI selected tool list still drives `event_agent.enabled_tools`.
- Full suite passes.