# ui_open_app

Open an application by name or bundle ID and return an accessibility tree summary of its windows and top-level UI elements. Requires Accessibility permissions.

Agent View of the PolicyLayer registry record for `ui_open_app`. HTML page: https://policylayer.com/tools/heznpc-airmcp/ui-open-app

## Facts

- Tool: `ui_open_app`
- Server: AirMCP (`airmcp`) — https://policylayer.com/tools/heznpc-airmcp.md
- Install: `npx -y airmcp`
- Homepage: https://github.com/heznpc/AirMCP
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "ui_open_app",
    "arguments": {}
  }
}
```

## Why ui_open_app is rated High

This tool launches arbitrary applications on the user's macOS system, which is an external operation with side effects. While it doesn't delete data or move money, executing arbitrary app launches could be misused to open malicious or unwanted applications. The accessibility tree read-back is secondary to the primary action of opening an app.

From the tool's own definition: "'Open an application by name or bundle ID' — triggers an external operation (launching an app) whose effect depends on the argument provided"

## Use case

AI agents invoke ui_open_app to trigger actions in AirMCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches AirMCP:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "ui_open_app": {
      "limits": [
        {
          "counter": "ui_open_app_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on AirMCP (278)

- `close_tab` — Destructive — https://policylayer.com/tools/heznpc-airmcp/close-tab.md
- `delete_contact` — Destructive — https://policylayer.com/tools/heznpc-airmcp/delete-contact.md
- `delete_event` — Destructive — https://policylayer.com/tools/heznpc-airmcp/delete-event.md
- `delete_note` — Destructive — https://policylayer.com/tools/heznpc-airmcp/delete-note.md
- `delete_photos` — Destructive — https://policylayer.com/tools/heznpc-airmcp/delete-photos.md
- `delete_playlist` — Destructive — https://policylayer.com/tools/heznpc-airmcp/delete-playlist.md
- `delete_reminder` — Destructive — https://policylayer.com/tools/heznpc-airmcp/delete-reminder.md
- `delete_reminder_list` — Destructive — https://policylayer.com/tools/heznpc-airmcp/delete-reminder-list.md
- `delete_shortcut` — Destructive — https://policylayer.com/tools/heznpc-airmcp/delete-shortcut.md
- `memory_forget` — Destructive — https://policylayer.com/tools/heznpc-airmcp/memory-forget.md
- `move_note` — Destructive — https://policylayer.com/tools/heznpc-airmcp/move-note.md
- `quit_app` — Destructive — https://policylayer.com/tools/heznpc-airmcp/quit-app.md
- `remove_from_playlist` — Destructive — https://policylayer.com/tools/heznpc-airmcp/remove-from-playlist.md
- `semantic_clear` — Destructive — https://policylayer.com/tools/heznpc-airmcp/semantic-clear.md
- `semantic_index` — Destructive — https://policylayer.com/tools/heznpc-airmcp/semantic-index.md
- `spotlight_clear` — Destructive — https://policylayer.com/tools/heznpc-airmcp/spotlight-clear.md
- `system_power` — Destructive — https://policylayer.com/tools/heznpc-airmcp/system-power.md
- `trash_file` — Destructive — https://policylayer.com/tools/heznpc-airmcp/trash-file.md
- `activate_tab` — Execute — https://policylayer.com/tools/heznpc-airmcp/activate-tab.md
- `ai_agent` — Execute — https://policylayer.com/tools/heznpc-airmcp/ai-agent.md
- `ai_chat` — Execute — https://policylayer.com/tools/heznpc-airmcp/ai-chat.md
- `ai_plan_metrics` — Execute — https://policylayer.com/tools/heznpc-airmcp/ai-plan-metrics.md
- `connect_bluetooth` — Execute — https://policylayer.com/tools/heznpc-airmcp/connect-bluetooth.md
- `disconnect_bluetooth` — Execute — https://policylayer.com/tools/heznpc-airmcp/disconnect-bluetooth.md
- `drop_pin` — Execute — https://policylayer.com/tools/heznpc-airmcp/drop-pin.md
- `duplicate_shortcut` — Execute — https://policylayer.com/tools/heznpc-airmcp/duplicate-shortcut.md
- `edit_shortcut` — Execute — https://policylayer.com/tools/heznpc-airmcp/edit-shortcut.md
- `event_subscribe` — Execute — https://policylayer.com/tools/heznpc-airmcp/event-subscribe.md
- `generate_image` — Execute — https://policylayer.com/tools/heznpc-airmcp/generate-image.md
- `generate_structured` — Execute — https://policylayer.com/tools/heznpc-airmcp/generate-structured.md
- …and 248 more: https://policylayer.com/tools/heznpc-airmcp.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=heznpc-airmcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/heznpc-airmcp