GameMaker CLI + MCP server toolset
Project description
GameMaker MCP Tools
Project Features
gms: a Python CLI for GameMaker project operations (asset creation, maintenance, runner, etc).gms-mcp: an MCP server that exposes the same operations as MCP tools (Cursor is the primary example client).- TCP Bridge (optional): live, bidirectional game communication (commands + log capture) via
gm_bridge_install,gm_run_command, andgm_run_logs. Seedocumentation/BRIDGE.md. - Reliability-First Architecture: Custom exception hierarchy, typed result objects, and an execution policy manager replace monolithic exit calls and raw dictionaries. This enables structured error handling, consistent tool integration, and optimized performance (Fast assets, Resilient runner).
- Health & Diagnostics:
gm_mcp_healthprovides a one-click diagnostic tool to verify the local GameMaker environment.gm_diagnosticsprovides structured, machine-readable project diagnostics (JSON, naming, orphans, references) compatible with IDE problem panels. - Runtime Management:
gm_runtime_list,gm_runtime_pin, andgm_runtime_verifyallow precise control over which GameMaker runtime version is used for builds and execution. - Cross-Platform Runner Defaults:
gm_run/gm_compilenow default to the host OS target platform (macOS,Linux, orWindows) when not explicitly provided. - macOS Runner Launch Support: temp-output runs now detect and launch macOS
.appbundles by resolving the executable inContents/MacOS/. - GML Symbol Indexing & Code Intelligence:
gm_build_index,gm_find_definition,gm_find_references, andgm_list_symbolsprovide deep, fast, and filtered code analysis (definitions and cross-file references). - Introspection: complete project inspection with support for all asset types (including extensions and datafiles).
- MCP Resources: addressable project index and asset graph for high-performance agent context loading.
gms-mcp-init: generates shareable MCP config files for a workspace. Now auto-detects environment variables likeGMS_MCP_GMS_PATHto include in the generated config.
Install (recommended: pipx)
pipx install gms-mcp
PowerShell equivalent:
pipx install gms-mcp
Claude Code Plugin
For Claude Code users, install the plugin for the best experience:
/install-plugin github:Ampersand-Game-Studios/gms-mcp
This provides:
- Skills: 18 workflow guides + 7 reference docs
- Hooks: Automatic update checks and error notifications
- MCP Server: Auto-configured via uvx (no pip install needed)
For Other Tools (Cursor, VSCode, OpenClaw, etc.)
pip install gms-mcp
gms-mcp-init --cursor # or --vscode, --windsurf, --openclaw, etc.
For skill packs, OpenClaw users can install to user or workspace scope:
gms skills install --openclaw # user scope: ~/.openclaw/skills/
gms skills install --openclaw --project # workspace scope: ./skills/
Note: .openclaw/openclaw.json is for settings. Workspace skills are loaded from ./skills/.
For Codex
gms-mcp-init --codex
This writes a workspace .codex/mcp.toml file and prints the codex mcp add registration command.
Global config mode writes directly to ~/.codex/config.toml (merging server entries).
Use the printed command directly, or copy .codex/mcp.toml content into the [mcp_servers] section of your ~/.codex/config.toml.
Codex helpers:
gms-mcp-init --codex-checkprints detected Codex config paths and active server entry.gms-mcp-init --codex-check-jsonprints the same check output in machine-readable JSON.gms-mcp-init --codex-dry-run-onlyprints final merged payloads for workspace + global Codex config without writing files.gms-mcp-init --codex-app-setupruns one-shot Codex app setup: writes workspace config, previews global merge, then prints check + readiness summary.
Local Development Setup
If you are working on the gms-mcp codebase itself, follow these steps to set up a local development environment:
-
Clone and install in editable mode:
git checkout dev python3 -m pip install -e ".[dev]"
-
Initialize local and global MCP servers for testing: We recommend setting up two separate MCP server configurations in Cursor to test your changes:
- Global (
gms-global): For general use across all your GameMaker projects. - Local (
gms-local): Specifically for testing your current changes to the server.
Run these commands from the project root (zsh/bash):
# Global setup (names it 'gms-global' in Cursor) gms-mcp-init --cursor-global --server-name gms-global --mode python-module --python python3 --non-interactive # Local setup (names it 'gms-local' in Cursor) gms-mcp-init --cursor --server-name gms-local --mode python-module --python python3 --non-interactive
PowerShell equivalent:
# Global setup (names it 'gms-global' in Cursor) gms-mcp-init --cursor-global --server-name gms-global --mode python-module --python python --non-interactive # Local setup (names it 'gms-local' in Cursor) gms-mcp-init --cursor --server-name gms-local --mode python-module --python python --non-interactive
- Global (
-
Verify in Cursor: Go to Cursor Settings > Features > MCP to see your new servers. You may need to click "Reload" or restart Cursor to see changes.
Publishing (maintainers)
Publishing is automated via GitHub Actions (PyPI Trusted Publishing) on every push to main and on tags v*.
See RELEASING.md for the one-time PyPI setup and the first manual upload helper scripts.
CI Coverage
- Core CI runs on Ubuntu and Windows across Python
3.11-3.13. - Runner/session regression tests also run on macOS across Python
3.11-3.13, including a mockless smoke test that builds a real.appbundle structure and validates executable path resolution.
Quality Reports
Quality reports are generated during CI and published as quality-reports-* artifacts.
TEST_COVERAGE_REPORT.mdMCP_TOOL_VALIDATION_REPORT.mdcoverage.xmlpytest_results.xmlquality_summary.json
You can regenerate these locally with:
python scripts/generate_quality_reports.py
Use --skip-test-run to regenerate from existing CI artifacts:
python scripts/generate_quality_reports.py --skip-test-run --junit-xml build/reports/pytest_results.xml --coverage-xml build/reports/coverage.xml
X (Twitter) posting on main
This repo can post to X automatically when main is updated.
- Personality / voice:
.github/x-personality.md - Tweet staging file:
.github/next_tweet.txt
How it works
- When a commit lands on
main, GitHub Actions reads.github/next_tweet.txt. - If it contains the placeholder text (or is empty), it skips posting.
- If it contains a real tweet, it posts to X and then clears the file back to the placeholder.
Maintainer flow (dev -> pre-release -> main)
Because this repo promotes changes dev -> pre-release -> main, prepare the tweet during the pre-release -> main PR:
- Update
.github/next_tweet.txtwith the tweet (following.github/x-personality.md) - Merge to
main
Use with a GameMaker project (multi-project friendly)
Run this inside each GameMaker project workspace (or repo) to generate config:
gms-mcp-init --cursor
This writes .cursor/mcp.json and attempts to auto-detect the .yyp location to set GM_PROJECT_ROOT.
For a one-time setup that works across many projects, write Cursor's global config instead:
gms-mcp-init --cursor-global
Generate a Codex config from the current workspace:
gms-mcp-init --codex
Generate a global Codex entry in ~/.codex/config.toml:
gms-mcp-init --codex-global
Global mode merges with existing entries so it is safe to keep multiple MCP servers in the same file.
Inspect current Codex config resolution:
gms-mcp-init --codex-check
Preview final merged Codex payloads for local + global without writing:
gms-mcp-init --codex-dry-run-only
Print Codex check output as JSON (useful for app automation):
gms-mcp-init --codex-check-json
One-shot Codex app setup (recommended for new workspaces):
gms-mcp-init --codex-app-setup
Codex App Quickstart
- Run
gms-mcp-init --codex-app-setupin your GameMaker workspace. - Confirm the output says
Ready for Codex app: yes. - If needed, run
gms-mcp-init --codex-check-jsonand verifyactive.scopeisworkspace. - Use
gms-mcp-init --codex-dry-run-onlybefore changing global config to preview merged TOML safely.
Canonical Client Workflow
All clients now support the same canonical action surface:
gms-mcp-init \
--client <cursor|codex|claude-code|claude-desktop|antigravity|gemini|vscode|windsurf|openclaw|generic> \
--scope <workspace|global> \
--action <setup|check|check-json|app-setup>
Optional:
--config-path /custom/pathto override default config location--safe-profileto enforce conservative env defaults
Examples:
# Cursor setup + readiness check
gms-mcp-init --client cursor --scope workspace --action app-setup
# Codex machine-readable readiness
gms-mcp-init --client codex --scope workspace --action check-json
# Claude Desktop global plugin sync
gms-mcp-init --client claude-desktop --scope global --action setup
# Gemini alias (Antigravity path)
gms-mcp-init --client gemini --scope global --action app-setup
# OpenClaw app setup + workspace skills install
gms-mcp-init --client openclaw --scope workspace --action app-setup \
--openclaw-install-skills --openclaw-skills-project
For parity status and supported defaults, see documentation/CLIENT_SUPPORT_MATRIX.md.
Generate example configs for other MCP-capable clients:
gms-mcp-init --vscode --windsurf --antigravity --openclaw
Set up Antigravity global config (recommended):
gms-mcp-init --antigravity-setup
This merges into ~/.gemini/antigravity/mcp_config.json, writes atomically, creates a timestamped backup on overwrite, and enables a conservative safety profile by default:
GMS_MCP_ENABLE_DIRECT=0GMS_MCP_REQUIRE_DRY_RUN=1
Check Antigravity readiness:
gms-mcp-init --antigravity-check
Print Antigravity check output as JSON:
gms-mcp-init --antigravity-check-json
One-shot Antigravity app setup:
gms-mcp-init --antigravity-app-setup
Use a custom Antigravity config path:
gms-mcp-init --antigravity-setup --antigravity-config-path /path/to/mcp_config.json
Opt in to the conservative safety profile for Antigravity example configs too:
gms-mcp-init --antigravity --safe-profile
When GMS_MCP_REQUIRE_DRY_RUN=1 is set, you can allow specific destructive tools with:
export GMS_MCP_REQUIRE_DRY_RUN_ALLOWLIST=gm_asset_delete,gm_workflow_delete
Or generate everything at once:
gms-mcp-init --all
Monorepos / multiple .yyp
If multiple .yyp projects are detected in a workspace:
gms-mcp-initwill warn and (when interactive) prompt you to pick one.- In non-interactive environments, it defaults
GM_PROJECT_ROOTto${workspaceFolder}(safe).
Force a specific project root:
gms-mcp-init --cursor --gm-project-root path/to/project
Preview output without writing files:
gms-mcp-init --cursor --dry-run
Code Intelligence & Introspection
The MCP server provides comprehensive project analysis capabilities:
GML Symbol Indexing (gm_build_index)
Build a high-performance index of all functions, enums, macros, and global variables in the project. This is required for advanced code intelligence tools.
Symbol Definition (gm_find_definition)
Find the exact location and docstrings for any GML symbol in your project.
Find References (gm_find_references)
Search for all usages of a specific function or variable across your entire codebase.
List Symbols (gm_list_symbols)
List all project symbols with filtering by type, name substring, or file path.
Asset Listing (gm_list_assets)
List all assets in your project, optionally filtered by type:
- Supported types: script, object, sprite, room, sound, font, shader, path, timeline, tileset, animcurve, sequence, note, folder, extension, includedfile (datafiles)
Asset Reading (gm_read_asset)
Read the complete .yy JSON metadata for any asset by name or path.
Reference Search (gm_search_references)
Search for patterns across project files with:
- Scopes:
all,gml,yy,scripts,objects,extensions,datafiles - Modes: literal string or regex
- Options: case sensitivity, max results
Asset Graph (gm_get_asset_graph)
Build a dependency graph of assets with two modes:
- Shallow (fast): Parses
.yyfiles for structural references (parent objects, sprites, etc.) - Deep (complete): Also scans all GML code for runtime references like
instance_create,sprite_index,audio_play_sound, etc.
MCP Resources
Pre-built, cacheable project data for agents:
gms://project/index: Complete project structure (assets, folders, room order, audio/texture groups, IDE version)gms://project/asset-graph: Asset dependency graphgms://system/updates: Returns a human-readable message if a newer version ofgms-mcpis available on PyPI or GitHub.
Update Notifier
The server automatically checks for updates on startup and during common operations:
- Tool:
gm_check_updatesreturns structured update info. - Auto-check:
gm_project_infoincludes anupdatesfield. - Resource:
gms://system/updatesprovides a quick text status.
CLI usage
Run from a project directory (or pass --project-root):
gms --version
gms --project-root . asset create script my_function --parent-path "folders/Scripts.yy"
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