I Built a Godot MCP Server Because Existing Ones Couldn't Let AI Test My Game
Source: Dev.to
The Problem
I make games in Godot and use AI (Claude Code) to write code daily.
The workflow always had the same bottleneck:
AI writes code → I run the game → I check if it works → I report back → AI fixes → I run again…
That “run and check” part adds up, especially when tweaking UI, testing edge cases, or iterating on a mechanic. I wanted to hand off the entire build‑test‑fix cycle to AI.
Existing Godot MCP servers fell short:
| Server | Cost | # Tools | Main Limitations |
|---|---|---|---|
| Free (godot‑mcp, etc.) | Free | ~13 | No ability to launch the game, let alone play it or take screenshots |
| Paid (GDAI MCP) | $19 | ~30 | Still missing input simulation and runtime analysis |
None could do what I needed: AI builds the game, runs it, tests it, and fixes what’s broken—without any manual steps.
So I built Godot MCP Pro – 84 tools across 14 categories, including input simulation, runtime analysis, and screenshot capture, enabling AI to autonomously test a running game.
Demo: One Prompt → Complete Reversi + AI Playtest
The Prompt (summary)
Build a complete Reversi game in this Godot project.
Single scene, single script, all rendering via _draw().
Requirements: 8×8 board, pieces, highlights, flip animation,
standard rules, score display, restart button...
After building, set as main scene and play it.
Then playtest: play 4 moves, screenshot after each,
fix anything that's wrong.
The key is the last instruction—“playtest it yourself, fix anything that’s wrong.” That single line turns the AI from a code generator into a QA tester.
What Happened
Build Phase (~2 min)
AI autonomously chains tool calls to build the game:
create_script("main.gd") → Full game logic in one file
create_scene("main.tscn") → Scene with Node2D root
attach_script → Wire script to root
add_node × 4 → Score, Turn, Message labels + Restart button
save_scene
set_project_setting
reload_project
play_scene
The editor updates in real time: nodes appear in the scene tree, and the game window opens with a fully rendered Reversi board.
Playtest Phase (~2 min)
AI takes a screenshot, inspects the board, clicks a cell, takes another screenshot to verify:
| Move | Outcome |
|---|---|
| 1‑2 | Successful. AI confirms piece placement, flipping, and score updates after each move. |
| 3 | AI clicks B2 → screenshot shows “B2 was not a valid move. Score didn’t change.” → AI reads the yellow highlights, discovers the correct move (C4) → self‑corrects → success. |
| 4 | AI clicks E2 → screenshot shows failure → AI self‑corrects to E3 → success. |
The AI made mistakes, but it caught them from the screenshots and fixed them without any human input. This is the workflow I wanted: tell the AI to test, and it figures out the rest.
Report
After testing, the AI outputs a full checklist:
| Feature | Status |
|---|---|
| 8×8 board rendering | OK |
| Piece drawing with outlines | OK |
| Valid move highlights | OK |
| Last‑move indicator | OK |
| 8‑direction flip logic | OK |
| Flip animation | OK |
| Score and turn display | OK |
| Auto‑pass handling | OK |
| Restart button | OK |
How It Works
Architecture
AI Assistant ←─MCP/stdio──→ Node.js Server ←─WebSocket──→ Godot Editor Plugin
MCP (Model Context Protocol) is an open protocol by Anthropic that gives AI access to tools. Godot MCP Pro implements this protocol with 84 tools across 14 categories.
Four tool categories that enable autonomous testing
| Category | Why it matters |
|---|---|
play_scene / stop_scene | AI can launch and stop the game |
simulate_mouse_click / simulate_key / simulate_sequence | AI can send input to the running game |
get_game_screenshot | AI can see the running game |
get_game_scene_tree / get_game_node_properties | AI can read runtime state |
Without these, AI can write code but can’t verify it works. With them, AI closes the loop.
Why Not Just Edit Files?
File editing gives you code generation, but it doesn’t provide:
- Game launch/stop control
- Input simulation (keyboard, mouse, action sequences)
- Screenshot capture from the running game
- Runtime state inspection (live scene tree, node properties)
- Undo/redo (all MCP mutations go through Godot’s
UndoRedoManager)
The build → test → fix cycle needs bidirectional communication with the editor—that’s the whole point.
Full Tool List (84 tools / 14 categories)
| Category | # | What it does |
|---|---|---|
| Project | 7 | Filesystem, settings, UID conversion |
| Scene | 9 | Create, open, delete, instance, play/stop |
| Node | 11 | Add, delete, rename, properties, signals |
| Script | 6 | List, read, create, edit, attach |
| Editor | 8 | Screenshots, errors, GDScript execution |
| Input Simulation | 5 | Keyboard, mouse, actions, sequences |
| Runtime Analysis | 4 | Live scene tree, properties, monitoring |
| Animation | 6 | Create, tracks, keyframes |
| TileMap | 6 | Cell ops, fill, info |
| Theme & UI | 6 | Colors, constants, fonts, styleboxes |
| Shader | 6 | Create, edit, parameters |
| Batch Ops | 5 | Search, bulk changes, dependencies |
| Profiling | 2 | Performance monitors |
| Export | 3 | Presets, build commands |
Input simulation, runtime analysis, signal management, animation, tilemap, shader, and profiling tools are exclusive to Godot MCP Pro—no other Godot MCP server offers them.
How I Actually Use It Day‑to‑Day
The Reversi demo is a showcase. In practice, the most useful things are more mundane:
- UI setup – “Set this Label’s font to 24, anchor to center‑top.” AI changes it directly in the editor.
- Signal wiring – “Connect this button’s
pressedsignal toon_restart.” Done without opening the Node dock. - Prototyping – “Make a temporary health bar that follows the player.” AI creates the node, adds it to the scene, and wires the script.
Because the AI can see the running game, interact with it, and inspect the live scene tree, it can iterate far faster than a pure file‑editing workflow.
Bottom Line
Godot MCP Pro gives AI the tools it needs to build, launch, test, and fix a game entirely inside the editor. The result is a dramatically tighter feedback loop and a workflow where the “run and check” step is fully automated.
Player Dash When Pressing Shift — AI writes the code, launches the game, tests it
Bug investigation: “Run the game, do X, then read the player’s position and velocity” — AI reports back with actual runtime values.
It lets me focus on game design and final decisions while AI handles the editor busy‑work.
Getting Started
Requirements
- Godot 4.x (4.3+)
- Node.js 18+
- MCP‑compatible AI client (Claude Code, Claude Desktop, Cursor, Cline, etc.)
Get it from godot-mcp.abyo.net
- Copy
addons/godot_mcp/into your Godot project. - Enable the plugin in Project Settings → Plugins.
Add to your AI client’s MCP config
{
"mcpServers": {
"godot-mcp-pro": {
"command": "node",
"args": ["path/to/mcp/server/build/index.js"]
}
}
}
- Enter fullscreen mode
- Exit fullscreen mode
Godot MCP Pro
- 84 tools
- 14 categories
- $5 one‑time, lifetime updates