Playcaller

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An MCP server that lets AI agents play-test Unity games like a real player. It provides screenshot capture, input simulation (tap, drag, flick, key press), Play Mode control, and more — all accessible from AI agents.

In short, it's a Playwright MCP for Unity.

Features

• Game View screenshot capture
• Tap, drag, flick, and key input simulation
• Play Mode start / stop / pause
• Scene GameObject hierarchy inspection
• Console log retrieval
• AssetDatabase refresh
• Menu item execution
• Editor state retrieval

Limitations

• Not suited for testing fast-paced action games
• Not suited for evaluating overall game experience
• Not suited for judging visual effects quality

Requirements

• Unity 2022.3 or later
• Python 3.10 or later (uv recommended)

Setup

1. Install the Unity package

1. Open Window > Package Manager in the Unity Editor menu bar
2. Click the + button in the top-left corner
3. Select Add package from git URL...
4. Enter the following URL and click Add

https://github.com/takashicompany/playcaller.git

Newtonsoft.Json (com.unity.nuget.newtonsoft-json) will be installed automatically if not already present.

2. Register the MCP server

Run the following command:

claude mcp add playcaller -- uvx playcaller

If something doesn't work, try asking the AI for help.

3. Verify the connection

Launch Claude Code while the Unity Editor is open, and it will connect automatically.

Updating

Unity package

1. Open Window > Package Manager
2. Select Playcaller from the list
3. Click Update

MCP server (PyPI)

uvx --upgrade playcaller

and restart Claude Code.

Notes

Run In Background

If the game does not progress after starting Play Mode via MCP, the project's "Run In Background" setting may be disabled. Enable it in Edit > Project Settings > Player > Resolution and Presentation > Run In Background, or set Application.runInBackground = true in your game code.

HDR projects

In URP/HDRP projects with HDR enabled, playcaller_screenshot may hang due to a known Unity issue. Use playcaller_read_gameview_pixels instead, which reads the GameView's internal buffer directly and works with HDR.

MCP Tools

Tool	Description
playcaller_screenshot	Capture a Game View screenshot
playcaller_read_gameview_pixels	Capture Game View by reading internal buffer (HDR compatible)
playcaller_tap	Tap at specified coordinates
playcaller_multi_tap	Execute multiple taps in sequence
playcaller_drag	Drag operation
playcaller_flick	Flick (quick swipe) operation
playcaller_key_press	Keyboard input
playcaller_playmode	Start / stop / pause Play Mode
playcaller_wait	Wait for a specified time or frame count
playcaller_console_log	Retrieve Unity console logs
playcaller_refresh	Refresh AssetDatabase
playcaller_get_hierarchy	Get the GameObject hierarchy in the scene
playcaller_get_gameobject	Get detailed info about a specific GameObject
playcaller_execute_menu_item	Execute a Unity Editor menu item
playcaller_get_editor_state	Get the current editor state
playcaller_game_query	Send a custom query to the running game
playcaller_set_game_view_size	Set the Game View resolution