reforge-mcp

An MCP server that answers questions about Arma Reforger / Enfusion from your installation, and can optionally drive the Workbench editor.

MIT licensed. No Bohemia content is redistributed — every index is generated locally from the game you already own, and stamped with the build it came from.

Why this exists

Reforger's shipped API documentation is two engine versions behind, cannot be regenerated on current Tools builds, and gets some core editor inheritance backwards — at least one class is documented as inheriting from its own subclass. If you are writing anything non-trivial against the engine, you are working from a map of a different country.

This server reads the game you actually have: the .pak archives, the resource database, the live editor. When it answers, it tells you which build the answer came from.

It is useful on its own. It knows nothing about any particular mod.

What it can do

Read the engine (default, no editor needed):

• symbol_lookup — a class or enum's real declaration, inheritance chain, members, methods, and what uses it

• source_read / source_grep — read one symbol or grep inside the .pak archives, where ordinary tools cannot look

• guid_resolve / path_guid / resource_refs — resolve resource GUIDs either way, and find who overrides, inherits from, or references a resource

• config_merge_preview — preview a same-GUID override before it silently replaces vanilla content

• prefab_resolve — a prefab's merged component set with each component's origin

• addon_deps, version_info, capabilities, diagnose

Drive the editor (opt-in, needs Workbench running):

• Live reads: editor state, entity list, resolved properties, layers, prefabs, resources

• Writes: create/modify/delete entities, edit components, layers, prefabs, scripts, string tables, and control the session

• wb_inspect — generic runtime reflection over live objects

• wb_process / wb_dialogs — start, close and restart the editor, and clear the modal dialogs that block its automation bridge

Install

Requirements: Node.js 20+, Arma Reforger, Arma Reforger Tools (only for editor features).

git clone <this repo>
cd reforge-mcp
npm install
npm run build

Copy reforge.config.example.json to reforge.config.json and set your paths:

{
  "profile": "research",
  "gamePath": "C:\\Program Files (x86)\\Steam\\steamapps\\common\\Arma Reforger",
  "toolsPath": "C:\\Program Files (x86)\\Steam\\steamapps\\common\\Arma Reforger Tools",
  "steamAppsPath": "C:\\Program Files (x86)\\Steam\\steamapps",
  "projectPath": "C:\\Users\\<you>\\Documents\\My Games\\ArmaReforgerWorkbench\\addons",
  "roots": []
}

Build the indexes (a few seconds — they come from your install, not from us):

npx reforge index build

Register it with your MCP client as a stdio server running node dist/index.js.

Check it came up:

npx reforge diagnose

Profiles — read this before enabling writes

The server ships in research mode. In that mode the write tools do not exist: they are absent from the tool list, not merely disabled. An assistant driving the server cannot see, name, or attempt a capability it has not been granted.

{ "profile": "research" }    // default — 20 tools, 0 writers, no editor needed
{ "profile": "workbench" }   // opt-in  — 60 tools, 25 writers, drives your editor

Switching to workbench is a real decision. It lets the server modify files in the mod roots you declare, and change a live editor session. Read WARNINGS.md first.

What is not in this repository, and why

No indexes. The data/ directory is absent on purpose. Indexes are derived from your Bohemia installation, so shipping them would be redistributing game content. Run npx reforge index build; it takes seconds.

One shared addon GUID. workbench-addon/addon.gproj ships a real, collision-checked GUID (97A138F130D5D9BA) so it works out of the box. Enfusion identifies addons by GUID and collisions are silent, so if you fork this and intend to distribute your fork, mint your own 16-character uppercase hex GUID rather than shipping two different addons claiming the same identity. Using it unmodified, locally, is fine.

No knowledge base. kb_search ships, but the distilled kb/ corpus does not — its licensing needs review before redistribution. The tool degrades quietly: it warns that the index is missing and answers nothing, rather than failing.

No experiment runner. exp_run exists upstream but is tied to one specific framework's validation plan and its instrumented components. It is not a general Enfusion capability, so it is not here.

The other half: handlers

The editor features need a small addon installed into Workbench. Workbench ships a network listener but no functions — a handler is a script class that says "when this request arrives, run this inside the editor and send this back". Without the addon, every wb_* tool fails to connect; everything else still works.

See HANDLERS.md for what they are, how to install them, and why they are a separate addon.

Documentation

Design commitments

These are the things the server will not do, and they are enforced in code rather than documented as intentions:

• It never publishes. There is no Workshop upload tool, no publish tool, and a test that fails if one is ever added.

• It answers with a build stamp. Every index records which game build it was generated from, so a stale answer says so instead of being quietly wrong.

• Writes are dry-run by default, return a real diff, and need a single-use plan id to apply.

• Reversibility is claimed per operation, never per tool. Operations that cannot be undone record no inverse and say so — a fabricated undo that looks like a restore is worse than none.

• Allowlists, never blocklists, for menu actions and for read-only enforcement.

Licence

MIT. See LICENSE.

Arma Reforger and Enfusion are trademarks of Bohemia Interactive. This project is not affiliated with or endorsed by Bohemia Interactive. It redistributes no game content.