RPG Maker MV Ultimate MCP

🎮 RPG Maker MV Ultimate

An AI copilot that builds, understands and watches your RPG Maker MV game

Quick start · What it does · Map generation · Live bridge · Intelligence · Tools

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A Model Context Protocol server that lets an AI agent work on a real RPG Maker MV project on disk — database, maps, events, plugins, system — through 13 consolidated tools validated against the actual engine, so what comes out is coherent and playable.

It does three things that are usually missing:

🏗️ Builds	Generates maps that look hand-made, wires events from presets, and edits every database with real IDs instead of invented ones.
🧠 Understands	Reads the whole project and answers why the door never opens, which map nobody can reach, which skill breaks the game.
👀 Watches	Runs the game and reports back: exceptions, player position, screenshots — and reloads a map you just edited without losing the save.

⚡ Quick start

1 — Add it to your MCP client. No clone needed; the package ships an executable.

{
  "mcpServers": {
    "rpgmaker-mv": {
      "command": "npx",
      "args": ["-y", "rpgmaker-mv-mcp"],
      "env": {
        "RPGMAKER_PROJECT_PATH": "C:/path/to/your/RPGMakerMV/project"
      }
    }
  }
}

# Claude Code, user scope
claude mcp add rpgmaker --scope user \
  --env RPGMAKER_PROJECT_PATH="C:/path/to/project" \
  -- npx -y rpgmaker-mv-mcp

# From source
git clone https://github.com/DiegoLopez0208/RpgMakerMVUltimate-MCP
cd RpgMakerMVUltimate-MCP
npm install && npm run build
RPGMAKER_PROJECT_PATH=/path/to/your/project npm start

MCP clients load tool definitions once at startup, so restart the client after adding or upgrading the server.

2 — Point it at a project. RPGMAKER_PROJECT_PATH is the folder containing data/, js/ and index.html. The server starts without it; call set_project_path at runtime instead if you prefer.

3 — Let the agent look around first.

get_project_context { detail: "full" }        → what exists, with real IDs
analyze_project     { view: "overview" }      → health, counts, unreachable maps

Works with Claude Desktop, Claude Code, opencode, and any MCP-compatible client.

🧭 What it does

flowchart LR
    A["🤖 Agent"] -->|"generate_map · manage_map_event"| B["📁 Project on disk"]
    B -->|"validate · balance · metrics"| A
    B -->|"playtest"| C["🎮 Running game"]
    C -->|"exceptions · position · screenshots"| A
    A -->|"reload_map"| C

The bottom half of that loop is what the bridge adds. Before it, the agent wrote files and hoped.

🗺️ Map generation

Two paths, both behind generate_map. Pick by whether your project uses RTP art.

	mode: "procedural" (default)	mode: "semantic"
How	Clones a hand-authored map from the 106 bundled RTP templates, closest size first	Lays out a mission graph, then paints it through a tileset profile
Looks like	Real multi-tile buildings, walls, furniture	Rooms and corridors shaped by what the space is for
Tilesets	RTP, or close to it	Any — DLC, itch.io, custom
Guarantees	Same seed → same map	Same seed → same map, and the key is always reachable before the door it opens

The knowledge-driven path

{ "mode": "procedural", "theme": "town", "name": "Riverbend", "width": 40, "height": 30 }

Themes with a matching template — town, village, dungeon, interior, castle, world and more — clone a real map instead of painting tile noise. Themes without one (beach, swamp, desert…) fall back to Perlin terrain, BSP dungeons and cellular caves. Combat themes auto-wire random encounters from your existing troops; town and village auto-create enterable house interiors with two-way warps.

Themes · forest town village castle dungeon cave beach desert swamp ruins interior snow harbor volcano sewer fortress magic_forest magic_interior space_interior space_exterior world

Other modes: blank (empty canvas), themed (simple layout), template (one specific bundled map), batch (many at once), duplicate (copy an existing map).

The tileset-independent path

The bundled templates are raw MV map JSON, so their tile IDs only mean anything on RTP sheets. Change the tileset and the map turns to noise. semantic keeps the layout abstract until the last moment:

manage_system { action: "mine_templates" }               # learn from THIS project
generate_map  { mode: "semantic", tilesetId: 5, rooms: 6, seed: 42 }

• Mining reads every map you already made and derives semantic layouts (ground / wall / water / prop / door, multi-tile props kept whole), a tileset profile naming the concrete tile your project uses for each role, and token adjacency counts. Nothing in the project is modified — everything lands in .mcp-cache/.
• Generating builds the mission first — entrance → key → locked door → treasure → boss → exit, plus side rooms — as a graph whose edges are the only ways through, then paints it. Because the lock is an edge and the key sits on the entrance side of it, the map is solvable by construction. Autotile shapes are recomputed at the end from the finished neighbourhood, never guessed cell by cell.
• The result includes markers naming the cell of every mission role, which is where to put events with manage_map_event.
• Pass a mined templateId (e.g. "mined-3") to re-materialise one of your own maps onto a different tileset.

🔌 The live bridge

playtest on its own is fire-and-forget: the game opens and nothing comes back. The bridge closes the loop.

manage_system { action: "install_bridge_plugin" }   # once per project
manage_system { action: "bridge_start" }            # opens ws://127.0.0.1:32123
manage_system { action: "playtest" }                # the game connects on its own
manage_system { action: "bridge_telemetry", types: ["exception", "log"] }

sequenceDiagram
    participant A as 🤖 Agent
    participant S as 🖥️ MCP server
    participant G as 🎮 Game (nwjs)
    A->>S: edit_map
    S->>S: atomic write to Map002.json
    A->>S: bridge_command reload_map
    S->>G: reload_map
    G->>G: reserveTransfer + _needsMapReload
    G-->>S: reload_complete
    A->>S: bridge_screenshot
    S->>G: capture_screenshot
    G-->>S: PNG in base64
    S-->>A: path for analyze_image

• 📡 Telemetry — exceptions with stack traces, console.error/warn, scene changes, player position, which event command is executing (so a hung event can be pinpointed), FPS and heap. Frames are consumed as you read them unless you pass peek.
• ♻️ Hot reload — reload_map re-reads the current MapXXX.json and rebuilds the scene without losing party state: it reserves a transfer to the player's own position with _needsMapReload, the engine's own reload seam, rather than rebuilding Spriteset_Map by hand. reload_database re-reads one data file; System.json and Tilesets.json need a fresh playtest and are refused with an explanation.
• 📸 Screenshots — bridge_screenshot saves a PNG under .mcp-cache/screenshots/ and returns the path, ready for analyze_image.

🔒 Security

The plugin returns before anything else runs unless the game is under NW.js and was launched with a test argument. A deployed build a player double-clicks never reaches the socket code, or even require('fs').

It checks every argument rather than only argv[0] the way Utils.isOptionValid does, because playtest passes the project path first. So a deployed build deliberately launched with a literal test argument would get past the guard — and then find no handshake file, and never connect.

The server binds 127.0.0.1 only, refuses any upgrade carrying a browser Origin (cross-site WebSocket hijacking), and requires the session token from .mcp-bridge.json — compared in constant time — within 5 seconds or the connection is dropped.

The command surface is a fixed allowlist with no eval primitive.

🔍 Project intelligence

analyze_project is read-only and fully offline. It models the whole project once, so an agent can reason about a game it did not build.

View	Answers
overview	Call this first. Counts, health summary, maps unreachable from the start
validate	Every consistency problem at once — see below
explain	Why does this never happen? e.g. "Switch 12 is gated in 3 places but never set ON"
usage	Every event, common event and troop that touches a switch/variable/item, with read-write roles
graph	The map transfer network and what is reachable
ast	One event's logic as a readable tree
plugins	What plugins the project uses, their parameters and commands
critique	A designer's opinion on one map: dead space, clutter, event spread, monotony
metrics	The same map measured — see below
balance	Database entries that are out of line with their peers — see below
refactor	Command sequences copy-pasted across events, worth extracting into a Common Event
search	Find things by meaning across names, dialogue and descriptions
index	The structured digest the other views are built on

Broken transfers, missing map files, dangling common-event/item/troop references, duplicate IDs, named-but-unused switches and variables, a bad starting position, unreachable maps — and actor names written into dialogue as \N[id] that do not resolve.

That last one is worth its own sentence: the engine resolves \N[id] at draw time, not from any structural parameter, so a bad id passes every other check and the editor shows nothing wrong. The line just renders in-game with a hole where the name should be, and a player finds it before you do.

• Reachability — flood fill from the real entry point. Walkable tiles the player can never get to, and events with no reachable tile beside them, are softlocks rather than style notes.
• Dead space — the unreachable share of the rectangle, against a band for expected (interior / dungeon / exterior).
• Shape — the walkable area thinned to a one-cell skeleton and read as a graph: endpoints, junctions, cycles, critical path, linearity. Linearity near 1 is a corridor with no choice to make.
• Variety — Shannon entropy over 5×5 tile windows: the monotonous-floor problem, measured.
• Tension — for maps with random encounters, how many steps the player is from a shop, inn or save point.

A skill dealing 400 damage is fine in a game where everything does, and broken in one where nothing else breaks 60. So each entry is scored on a power metric and compared against the others in its category: damage per MP for skills, gold per point of ATK+MAT for weapons, gold per DEF+MDF for armors, HP per EXP for enemies.

The comparison is leave-one-out — an entry is judged against statistics it had no hand in creating. Included in its own numbers, a badly broken entry drags the mean toward itself until it stops looking unusual at all.

Damage formulas are parsed, never executed (tokenise → shunting-yard → evaluate). One that cannot be read statically is listed under unreadableFormulas rather than scored as zero damage, which would pull every average down and hide the very outliers you were looking for.

Narrow with category, loosen or tighten with thresholdSd (default 2).

Offline map inspection

• query_map { view: "ascii", mapId } — render a map as a character grid with event markers. The cheapest way to see a layout and pick coordinates.
• query_map { view: "validate", mapId } — lint one map for invalid tile IDs, broken transfers and missing event terminators.

🧰 The 13 tools

Tool	Purpose
query_database	List / get by ID / search any database (actors, classes, skills, items, weapons, armors, enemies, states, troops, tilesets, common events, animations)
create_database_entry	Create entries, with presets: damage_skill, healing_skill, buff_skill, state_skill, boss_enemy, encounter_troop
update_database_entry	Partial updates (incl. troops & animations); append commands to common events; add enemies to troops
delete_database_entry	Delete entries with reference-breakage warnings
query_map	Map tree, full map data, events, single event, lint, offline ASCII render
generate_map	Knowledge-driven, semantic, procedural, blank, themed, template, batch or duplicate
edit_map	Fill tile layers, set display names, organize the map tree, connect two maps, set encounters
manage_map_event	Create (presets: npc, chest, teleport, door, shop, inn, boss, puzzle_switch), update, convert an NPC into a merchant/inn/sign in place, delete, add commands, bulk-populate
manage_system	Title, switch/variable names, starting position, author a plugin, scaffold a project, playtest, open in editor, mine templates, and the live bridge
analyze_project	The read-only intelligence layer above
get_project_context	Project digest, asset index, per-tileset tile IDs, bundled-template catalog
set_project_path	Switch projects at runtime
analyze_image	Optional Vision-AI image analysis, plus offline tileset grid measurement and quadrant colors

The 101 fine-grained v4 tool names still work as call aliases. Set RPGMV_LEGACY_TOOLS=1 to advertise them too.

🛡️ Write safety

• Atomic. Every write goes to a temp file and is renamed over the target, so an interrupted call can never leave half-written JSON.
• Backed up. Rotated timestamped copies under .mcp-backups/ (last N, RPGMV_BACKUP_KEEP, default 10).
• Previewable. Pass dryRun: true to any mutating tool to see exactly what it would write, without touching disk.

⚠️ Close the RPG Maker editor while an agent is working. The editor holds the project in memory and will overwrite changes when it saves.

⚙️ Configuration

Variable	Required	Description
RPGMAKER_PROJECT_PATH	recommended	The project folder (the one with data/ and js/). Optional — set_project_path works at runtime
RPGMAKER_MV_INSTALL	for playtest	Engine install root, for playtest / open_editor / scaffold_project. Defaults to the standard Steam path
RPGMV_BRIDGE_PORT	optional	Loopback port for the live bridge (default 32123)
RPGMV_BACKUP_KEEP	optional	Backups kept per file (default 10)
RPGMV_LEGACY_TOOLS	optional	1 also advertises the 101 legacy tool names
VISION_API_URL	to enable vision	Base URL of an OpenAI-compatible vision endpoint. Unset = vision disabled
VISION_API_KEY	optional	Bearer token; only sent when set
VISION_MODEL	optional	Model name (default meta/llama-3.2-90b-vision-instruct)
VISION_API_PATH	optional	Endpoint path (default /v1/chat/completions)

analyze_image { mode: "ai" } sends a project image (tileset, sprite, screenshot, battler) to any OpenAI-compatible endpoint. Nothing is sent anywhere unless you configure it; the grid and colors modes and every other tool work fully offline.

# OpenAI
VISION_API_URL=https://api.openai.com VISION_API_KEY=sk-... VISION_MODEL=gpt-4o npm start
# Ollama (local, no key)
VISION_API_URL=http://localhost:11434 VISION_MODEL=llava npm start

Works with OpenAI, Ollama, LocalAI, NVIDIA NIM, vLLM, LiteLLM, or any OpenAI-compatible proxy.

🎓 Agent Skill

A portable Agent Skill teaches any model the crash-free workflow — build maps with generate_map, add content with manage_map_event presets, never hand-paint tiles or guess IDs. It lives at skill/rpgmaker-mv-mcp/SKILL.md.

# Claude Code / Claude.ai
npx degit DiegoLopez0208/RpgMakerMVUltimate-MCP/skill/rpgmaker-mv-mcp ~/.claude/skills/rpgmaker-mv-mcp
# opencode
npx degit DiegoLopez0208/RpgMakerMVUltimate-MCP/skill/rpgmaker-mv-mcp ~/.opencode/skills/rpgmaker-mv-mcp

Also listed in awesome-claude-skills.

📚 Knowledge base

File	Content
tile-ids.json	Tile ID ranges, autotile formula, sheet descriptions, layer meanings
passage-flags.json	Flag bits, common flags, passage check logic
event-commands.json	~140 event command codes with parameter schemas
enums.json	Scope, occasion, hitType, damageType, restriction, and the rest
trait-effect-codes.json	Trait codes 11-64, effect codes 11-45
database-schemas.json	Full schemas for every MV data type
image-paths.json	img/ directories, tileset slots, naming conventions
map-templates.json	Index of the 106 bundled reference maps
stamps.json	Mined multi-tile object stamps (trees, props) per tileset
maps/	The 106 RTP reference map JSONs used for template cloning

🚧 Known limitations & roadmap

• Decoration semantics are best-effort in the RTP-template path; rare multi-tile objects may land as single tiles. The mined path keeps multi-tile props whole.
• Town and dungeon layouts keep improving — planned: a central plaza or well as a landmark, houses in rows facing roads, fences and yards, richer road networks, more room variety.
• mode: "semantic" currently generates dungeon-shaped missions. Town and open-world mission grammars are next, as is using the mined adjacency counts to decorate rather than only to describe.
• balance compares like with like inside a category, so a boss will legitimately look like an outlier next to random encounters. Read the flag, not the verdict.
• The bridge is Windows/nwjs playtest only and needs its plugin installed in the project.
• Vision AI requires your own endpoint.

🛠️ Development

npm install
npm run build      # tsc compile (+ copies knowledge/ into dist/)
npm test           # vitest
npm run typecheck
npm run dev        # tsx watch mode

Where	What
src/server.ts	Tool handlers and MCP transport
src/toolDefinitions.ts + src/router.ts	The 13-tool surface and its routing
src/tools/*	Per-domain CRUD
src/utils/mapGenerator.ts	Template cloning and procedural generation
src/utils/graphGenerator.ts + src/utils/materialize.ts	Mission graphs and the semantic compiler
src/bridge/*	The loopback WebSocket and the in-game plugin
src/intel/*	The read-only layer behind analyze_project
knowledge/	Static reference data and bundled maps

💬 Feedback

Actively developed, and feedback is very welcome — bug reports, weird maps, missing tools, ideas. Open a GitHub Issue with what you asked the agent to do and what you got; an exported map JSON or a screenshot helps a lot.

MIT · Built for RPG Maker MV