# start_play

Enter play mode — starts running the game in the editor. Scripts execute, physics simulate, everything goes live

Agent View of the PolicyLayer registry record for `start_play`. HTML page: https://policylayer.com/tools/sbox/start-play

## Facts

- Tool: `start_play`
- Server: Sbox (`sbox-mcp-server`) — https://policylayer.com/tools/sbox.md
- Install: `npx -y sbox-mcp-server`
- Homepage: git+https://github.com/LouSputthole/Sbox-Claude.git
- 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": "start_play",
    "arguments": {}
  }
}
```

## Why start_play is rated High

This tool triggers execution of arbitrary game scripts and physics simulations within the s&box engine. While not destructive by itself, it activates live code execution whose effects depend on the current game state and scripts loaded in the editor. An AI agent could inadvertently cause unintended game behavior, resource consumption, or trigger scripts with side effects.

From the tool's own definition: "Tool description states: 'starts running the game in the editor. Scripts execute, physics simulate, everything goes live' — explicitly indicates code execution and simulation startup."

Risk signals: Bulk/mass operation — affects multiple targets

## Use case

AI agents invoke start_play to trigger actions in Sbox. 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 Sbox:

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

## Other tools on Sbox (206)

- `clear_cave_path` — Destructive — https://policylayer.com/tools/sbox/clear-cave-path.md
- `clear_forest_pois` — Destructive — https://policylayer.com/tools/sbox/clear-forest-pois.md
- `clear_terrain_features` — Destructive — https://policylayer.com/tools/sbox/clear-terrain-features.md
- `debug_clear` — Destructive — https://policylayer.com/tools/sbox/debug-clear.md
- `delete_gameobject` — Destructive — https://policylayer.com/tools/sbox/delete-gameobject.md
- `delete_script` — Destructive — https://policylayer.com/tools/sbox/delete-script.md
- `remove_component` — Destructive — https://policylayer.com/tools/sbox/remove-component.md
- `snap_to_ground` — Destructive — https://policylayer.com/tools/sbox/snap-to-ground.md
- `bake_navmesh` — Execute — https://policylayer.com/tools/sbox/bake-navmesh.md
- `bake_reflections` — Execute — https://policylayer.com/tools/sbox/bake-reflections.md
- `build_terrain_mesh` — Execute — https://policylayer.com/tools/sbox/build-terrain-mesh.md
- `console_run` — Execute — https://policylayer.com/tools/sbox/console-run.md
- `create_event_director` — Execute — https://policylayer.com/tools/sbox/create-event-director.md
- `create_npc_spawner` — Execute — https://policylayer.com/tools/sbox/create-npc-spawner.md
- `create_trigger_zone` — Execute — https://policylayer.com/tools/sbox/create-trigger-zone.md
- `debug_draw_box` — Execute — https://policylayer.com/tools/sbox/debug-draw-box.md
- `debug_draw_ray` — Execute — https://policylayer.com/tools/sbox/debug-draw-ray.md
- `debug_draw_sphere` — Execute — https://policylayer.com/tools/sbox/debug-draw-sphere.md
- `drive_player` — Execute — https://policylayer.com/tools/sbox/drive-player.md
- `execute_csharp` — Execute — https://policylayer.com/tools/sbox/execute-csharp.md
- `focus_object` — Execute — https://policylayer.com/tools/sbox/focus-object.md
- `frame_camera` — Execute — https://policylayer.com/tools/sbox/frame-camera.md
- `invoke_button` — Execute — https://policylayer.com/tools/sbox/invoke-button.md
- `invoke_method` — Execute — https://policylayer.com/tools/sbox/invoke-method.md
- `load_scene` — Execute — https://policylayer.com/tools/sbox/load-scene.md
- `network_spawn` — Execute — https://policylayer.com/tools/sbox/network-spawn.md
- `play_animation` — Execute — https://policylayer.com/tools/sbox/play-animation.md
- `play_sound_preview` — Execute — https://policylayer.com/tools/sbox/play-sound-preview.md
- `playtest` — Execute — https://policylayer.com/tools/sbox/playtest.md
- `recompile_asset` — Execute — https://policylayer.com/tools/sbox/recompile-asset.md
- …and 176 more: https://policylayer.com/tools/sbox.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=sbox · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/sbox