GameMaker MCP
GameMaker MCP servers for Claude Code, and where they stop
GameMaker now ships its own MCP server inside the official command line tool, and the community has built several more. Here is what an agent can realistically do with a GameMaker project, and when an engine with a full MCP server is the better fit.
The short answer
Yes, GameMaker has an MCP server. The official GameMaker CLI (gm-cli, from YoYoGames, Apache 2.0) runs one with gm-cli resourcetool mcp, which edits project resources without the IDE, and gm-cli itself compiles, runs and packages projects. Community servers add more. gamemaker-mcp by yearningss brings static analysis, Igor builds and a GML unit test runner, and gms-mcp by Ampersand Game Studios can send commands to a running game and read its logs. None of the servers we read lists tools to send player input or capture the game's screen, so judging feel and visuals stays with you. Summer Engine is the alternative if you want an agent that plays and checks the game itself, but it does not import GameMaker projects. Moving means rebuilding.
"GameMaker MCP" (or Game Maker MCP) used to mean a handful of hobby projects. That changed in 2026. Opera, which owns GameMaker, announced GM-CLI on 30 April 2026 alongside the new GMRT runtime, with Claude Code working in the terminal to query project structures, hunt down bugs and manage build configurations. The CLI's own README describes an MCP mode for its ResourceTool, and `gm-cli init` can set up AGENTS.md, MCP and Claude config for a new project.
So the question is no longer whether an MCP server exists for GameMaker. It is what an AI client can safely do with a GameMaker project, and what it still cannot see.
This page answers both with sources, lists the community servers worth knowing, and explains the alternative of building in an engine whose MCP server also runs the game, sends input, reads state and takes screenshots.
What it does
The official server in gm-cli
Run `npx @gamemaker/gm-cli@latest resourcetool mcp` with a path to your .yyp file. ResourceTool changes project files programmatically, so the agent can add and edit resources without opening the IDE. gm-cli gives you a guest licence automatically.
Compile and run from the terminal
gm-cli downloads the runtime and tools it needs, then compiles, runs and packages the project. GameMaker's own agent guidance tells Claude to use `gm-cli compile --errors-only` and `gm-cli run --errors-only` to debug.
GameMaker's rules for agents
The Claude file that gm-cli writes is blunt. Do not edit .yy or .yyp files yourself, use the resource tool MCP server instead, and edit .gml files with the agent's normal file tools.
Community servers
gamemaker-mcp by yearningss lists 225 tools, GML static analysis, guarded edits and Igor builds. GameMaker-MCP-Server by darkw3bb builds on Butterscotch Shenanigans' Stitch libraries. Petah's gamemaker-mcp serves the GML manual to your agent.
What the agent cannot see
No GameMaker server we read lists tools to send player input to the running game or capture a screenshot. The closest are the yearningss unit test runner, which builds the game and parses test results, and the optional TCP bridge in gms-mcp by Ampersand Game Studios, which sends supported commands to a running game and reads logs you instrument. The agent knows the game compiled and your tests passed. It does not know the jump feels floaty.
Summer as the engine-level alternative
Summer Engine is a desktop engine compatible with Godot 4. Its MCP server edits scenes and GDScript, presses play, sends scripted input, reads frame-stamped probes and takes screenshots, so the agent checks its own work in the running game.
How it works
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Step 1: Stay in GameMaker and connect the official server
Install Node.js, then run gm-cli from your project folder. Register
gm-cli resourcetool mcpwith your .yyp path in your MCP client, or letgm-cli initwrite the agent config for a new project. - 2
Step 2: Give the agent GameMaker's rules
Keep the generated Claude guidance in the project. Resource changes go through ResourceTool, GML changes go through normal file edits, and every change ends with a compile that returns errors only.
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Step 3: Add assets from any generator
Summer's cloud MCP tools generate sprites, sprite sheets, sound effects and music without the Summer engine running. Your agent downloads each file into the project folder. Add it with ResourceTool if it supports that resource type, or import it in the IDE. You still judge the result in the running game yourself.
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Step 4: Rebuild in Summer only if you want the full loop
If you want an agent that plays the game and verifies behaviour, rebuild a vertical slice in Summer. Rooms become scenes, objects become nodes with scripts, and your GML is the specification.
Two ways to run it
In Studio, or from the agent you already use
In Summer Studio
Summer Studio on the web generates sprites, backgrounds, sound effects, voice lines and music for any engine. Download the files and import them into GameMaker as usual.
Open the image tab in StudioFrom Claude, Cursor or Codex via MCP
You can register the Summer MCP next to gm-cli in the same client. Summer's cloud tools such as summer_generate_image, summer_slice_asset_sheet and summer_generate_audio work without the Summer desktop app, and summer_get_asset_download_url gives the agent a download link it can save into your GameMaker project folder.
Example prompt for your agent
Generate a 4 frame walk cycle sprite sheet for a green slime enemy in 32 by 32 pixel art, get me a download link for it, save it into my GameMaker project folder, and add it as spr_slime_walk if the gm-cli resource tool supports sprite import, otherwise tell me the steps to add it in the IDE.Set up the Summer MCP
| Server | Maker | What it covers | Licence |
|---|---|---|---|
| gm-cli resourcetool mcp | YoYoGames (official) | Edit project resources without the IDE; gm-cli also compiles, runs and packages | Apache 2.0 |
| gamemaker-mcp | yearningss | 225 tools, GML static analysis, guarded edits, Igor compile and package jobs, GML unit test runner | MIT |
| gms-mcp | Ampersand Game Studios | Assets, code navigation, diagnostics, Igor builds, optional TCP bridge that sends supported commands to a running game and reads logs you instrument | MIT |
| GameMaker-MCP-Server | darkw3bb | Create projects, scripts, objects and sprites from Cursor, built on Stitch | See repository |
| gamemaker-mcp | Petah | GML manual lookup and search for agents | See repository |
Sources: YoYoGames/gm-cli on GitHub
| Task | GameMaker with gm-cli | Summer MCP |
|---|---|---|
| Write and refactor game code | Yes, GML files | Yes, GDScript files |
| Create objects, rooms or scenes | Through ResourceTool | Scene tree tools |
| Compile and read errors | Yes, errors only mode | Script, debugger and diagnostics tools |
| Send input to the running game | Not listed for player input; gms-mcp sends supported commands through its bridge | Yes |
| Read state at a given frame | Not listed | Yes, frame-stamped probes |
| Screenshots of the game | Not listed | Yes, plus snapshot diffs |
| Generate art and audio | Use any external generator | Built in |
Pricing
What it costs
- Image, Nano Banana 2 Lite (1K)
- $0.07estimate
- Sound effect, 5 seconds
- $0.01
gm-cli and the community servers are free to run. Summer charges only for generation, from your usage balance. GameMaker's own licence terms apply to what you ship.
Prices are charged from your Summer usage balance. Generating assets needs a paid plan or a top-up: Pro is $20 a month and includes $20 of usage, and top-ups start at $10. The desktop engine itself is free to download.
See all plansExamples
Prompts that work, and what comes back
What works well with a GameMaker agent today, and one thing that needs a different engine.
Refactor GML
Prompt
Move the player's state logic out of the Step event into a struct-based state machine script. Keep behaviour identical and compile with errors only.
What you get
Edited .gml files and a clean compile. Whether behaviour is identical is for you to check by playing.
Create an object
Prompt
Add obj_coin with a Create event that sets a bob offset and a Step event that bobs it, using the resource tool for the object itself.
What you get
A new object registered in the project through ResourceTool and two event scripts written as GML.
Find a compile error
Prompt
The build fails after my last change. Compile with errors only and fix what it reports.
What you get
Compiler output parsed into file and line, and a targeted fix. This is where terminal agents shine in GameMaker.
Generate a sprite set
Prompt
Make a 16 by 16 pixel art coin, a heart and a key with one consistent palette.
What you get
Three images from Summer's generator, downloaded and added as GameMaker sprites.
Tune the jump by feel
Prompt
Play the game, jump onto the second ledge and tell me whether the player makes it.
What you get
Not possible with the GameMaker servers we read, since none lists input or screenshot tools. In Summer the agent sends input, probes the player and shows a screenshot.
What the GameMaker project format means for an agent
A GameMaker project is a .yyp file plus a .yy file for every resource, with your code in .gml files. The .yy files are JSON-like but not strict JSON (the yearningss server notes trailing commas), and they reference each other by name and path. An agent that edits them as text can leave a project that no longer opens. That is why GameMaker tells agents to use ResourceTool for resources.
GML files are different. They are plain code and an agent can read, write and refactor them well, especially with the manual available through `gm-cli manual`. Opera's announcement also stresses that project files are plain text and Git compatible, so commit before every agent session and review the diff.
Licensing to check before you ship
GameMaker's free tier is for non-commercial use. Selling a game needs the Professional commercial licence, and console export needs the Enterprise subscription. None of that changes with an MCP server. Check the current terms on GameMaker's own pricing page.
When to move a GameMaker project to an engine with a full MCP server
Move when the bottleneck is verification, not typing. If you spend your sessions running the game, describing what broke and pasting it back, an engine-level server removes that loop. Summer's agent plays the game, reads the state and fixes what it finds.
Summer does not import GameMaker projects. Third-party converters such as GM2Godot, which targets GameMaker LTS 2026 source projects and Godot 4.7 output, translate sprites, sounds, rooms and supported GML into a Godot project, but Summer has not tested their output, so plan on a rebuild. The rebuild is mechanical though. Rooms become scenes, objects become nodes with scripts, Create becomes a ready callback, Step becomes a per frame process callback, Draw becomes a draw callback and alarms become timers. Summer builds desktop games for Windows and macOS for Steam and itch.io. Web export is not available in Summer yet, so stay in GameMaker if browser builds matter to you.
Frequently asked questions
Is there an official GameMaker MCP server?
Yes. The official GameMaker CLI from YoYoGames runs ResourceTool as an MCP server with gm-cli resourcetool mcp. It needs the path to your .yyp file in MCP mode.
Can Claude Code work on a GameMaker project?
Yes. Opera announced Claude Code support in GM-CLI on 30 April 2026, and gm-cli can write the Claude config for a new project. Claude edits GML, changes resources through ResourceTool and compiles to read errors.
Does GameMaker have a built-in AI assistant?
We found no AI assistant inside the GameMaker IDE in GameMaker's own announcements. The official route Opera announced on 30 April 2026 is Claude Code working through GM-CLI in the terminal, with ResourceTool as the MCP server. GameMaker's Russell Kay told Game Developer the tools are complementary and opt-in.
Should the agent edit .yy and .yyp files directly?
No. GameMaker's own agent guidance says not to, because those files are hard to edit correctly by hand. Use the resource tool MCP server for resources and normal file edits for .gml code.
Can a GameMaker MCP server play my game and test it?
gm-cli can run the game and return errors. None of the GameMaker servers we read lists tools that send input to the running game or capture its screen, so judging feel and visuals stays with you.
Can Summer import my GameMaker project?
No. GameMaker projects and GML do not run outside GameMaker. Moving means rebuilding in Summer, with your art, audio and design reused and your GML as the specification.
Can I use Summer's generators with GameMaker?
Yes. Summer's cloud tools and Studio generate sprites, sprite sheets, sound effects and music for any engine. For an animated sprite, slice the sheet into frames with summer_slice_asset_sheet so each frame can become a sub-image of one GameMaker sprite, then add the files to your project.
Related tools and guides
Sources
- YoYoGames/gm-cli README
- gm-cli agent guidance (claude-contents.txt)
- GameMaker launches GMRT (Opera Newsroom, 30 April 2026)
- yearningss/gamemaker-mcp on GitHub
- darkw3bb/GameMaker-MCP-Server on GitHub
- Petah/gamemaker-mcp on GitHub
- GameMaker licences
- Ampersand-Game-Studios/gms-mcp on GitHub
- Infiland/GM2Godot on GitHub
- GameMaker incorporates Claude Code (Game Developer)
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Even if it is built in another engine.
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