valkyrie-mom-mcp

MCP (Model Context Protocol) server and Claude Code plugin for AI-assisted Mansions of Madness 2nd Edition scenario creation with Valkyrie.

What it does

This server exposes Valkyrie scenario editing as MCP tools, enabling AI assistants (Claude, etc.) to create, modify, validate, and build complete MoM scenarios. It auto-detects the Valkyrie editor directory so scenarios appear directly in the app.

The plugin bundles 7 skills covering advanced patterns (event loops, mythos scaling, tile placement chains, custom puzzles, etc.) and an autonomous scenario designer agent.

Install

As a Claude Code plugin (recommended)

claude plugin marketplace add thijs-hakkenberg/ValkyrieMCP
claude plugin install valkyrie-mom

This gives you:

• MCP server with 16 tools for scenario editing (auto-started)
• 7 skills: /scenario, /event-patterns, /tile-placement, /variables-and-mythos, /custom-monsters, /ui-and-puzzles, /items-and-distribution
• Scenario designer agent for autonomous scenario creation
• 5 MCP resources for format documentation

To update to the latest version:

claude plugin marketplace update valkyrie-mom
claude plugin update valkyrie-mom

To uninstall:

claude plugin uninstall valkyrie-mom

As a standalone MCP server (Claude Desktop, other MCP clients)

Add to your MCP client config (e.g., ~/.claude/mcp.json or Claude Desktop settings):

{
  "mcpServers": {
    "valkyrie-mom": {
      "command": "npx",
      "args": ["-y", "@thijshakkenberg/valkyrie-mom-mcp"]
    }
  }
}

This gives you the MCP tools and resources, but not the skills or agent (those require Claude Code).

From source

git clone https://github.com/thijs-hakkenberg/ValkyrieMCP.git
cd ValkyrieMCP
npm install
npx tsx src/index.ts   # Run MCP server via stdio

Skills

| Skill | Description | |-------|-------------| | /scenario | Guided end-to-end scenario creation workflow | | /event-patterns | Event loops, multi-question dialogues, silent events, token swaps, random events, variable branching | | /tile-placement | Standard placement chains, multi-entry tiles, naming conventions | | /variables-and-mythos | Variable system, mythos scaling formula, random generation, hero detection, content pack gating | | /custom-monsters | Custom activations, evade/horror events, round-based spawn triggering | | /ui-and-puzzles | Prologues, interactive journals, combination locks, built-in puzzle types | | /items-and-distribution | Random items, unique items, starting items, inspection events |

MCP Tools

Lifecycle

| Tool | Description | |------|-------------| | list_scenarios | List all scenarios in the Valkyrie editor directory | | create_scenario | Create a new scenario (defaults to Valkyrie editor dir) | | load_scenario | Load an existing scenario from a directory | | get_scenario_state | Get current scenario component/localization summary | | validate_scenario | Run all validation rules | | build_scenario | Save and build .valkyrie package |

Components

| Tool | Description | |------|-------------| | upsert_event | Create or update an event | | upsert_tile | Create or update a tile | | upsert_token | Create or update a token | | upsert_spawn | Create or update a monster spawn | | upsert_item | Create or update an item | | upsert_puzzle | Create or update a puzzle | | upsert_ui | Create or update a UI element | | delete_component | Delete a component with cascade reference cleanup | | set_localization | Set localization key-value pairs |

Map

| Tool | Description | |------|-------------| | get_map_ascii | Render tile layout as ASCII art | | suggest_tile_layout | Suggest coordinates for linear, L-shape, or hub-spoke layouts | | place_tile_relative | Compute position relative to an existing tile |

Reference

| Tool | Description | |------|-------------| | search_game_content | Search game content catalogs (846 entries across tiles, monsters, items, audio) |

MCP Resources

| Resource | URI | |----------|-----| | Event format docs | valkyrie://format/events | | Localization format docs | valkyrie://format/localization | | Component format docs | valkyrie://format/components | | Pattern reference | valkyrie://format/patterns | | Current scenario state | valkyrie://scenario/current |

MCP Prompts

| Prompt | Description | |--------|-------------| | create-scenario | Guided workflow for creating a new scenario | | review-scenario | Analyze a scenario for balance and completeness |

Valkyrie Editor Paths

The server auto-detects where Valkyrie stores editor scenarios:

| Platform | Path | |----------|------| | macOS / Linux | ~/.config/Valkyrie/MoM/Editor/ | | Windows | %APPDATA%\Valkyrie\MoM\Editor\ |

Scenario File Format

A scenario is a directory containing:

• quest.ini - Quest config and file listings
• events.ini - Event components (triggers, buttons, branching)
• tiles.ini - Map tile placements
• tokens.ini - Search, explore, interact, and wall tokens
• spawns.ini - Monster spawn configurations
• items.ini - Quest items
• ui.ini - UI elements (backgrounds, etc.)
• other.ini - Puzzles and misc components
• Localization.English.txt - CSV localization (key,value pairs)

Built scenarios are ZIP archives with a .valkyrie extension.

Validation Rules

The server validates scenarios against 12 rule categories:

1. Unique names - No duplicate component names
2. Required fields - Tiles have side, displayed events have buttons
3. Cross-references - All referenced components exist
4. Event graph - EventStart trigger exists, no unreachable/dead-end events
5. Event flow - Buttons vs event-ref consistency, silent event rules
6. Localization completeness - Event text, button labels, quest metadata
7. Format rules - Valid format version, type=MoM, tile rotations
8. Catalog references - Tile sides, monster names, items match game content
9. Tile connectivity - Tiles are spatially connected
10. Mythos structure - Proper mythos trigger configuration
11. Investigator token - TokenInvestigators setup and removal
12. Explore token - Explore tokens linked to tile reveal events

Development

npm test          # Run all tests (1015 tests across 30 files)
npm run test:watch # Watch mode
npm run lint       # Type check
npm run build      # Compile to dist/

Project Structure

.claude-plugin/    Plugin manifest
skills/            7 skill SKILL.md files
agents/            Scenario designer agent
src/
  io/              INI parser/writer, localization CSV, ZIP packager
  model/           ScenarioModel, LocalizationStore, component types
  validation/      12 rules + orchestrator
    rules/         Individual validation rule implementations
  tools/           MCP tool implementations
  resources/       Format documentation resources
  catalogs/        846-entry game content catalog
  server.ts        MCP server registration
  index.ts         Entry point (stdio transport)
tests/
  fixtures/        ExoticMaterial (reference scenario), MinimalScenario
  io/              IO layer tests
  model/           Model layer tests
  tools/           Tool tests
  validation/      Validation rule tests
  golden.test.ts   Round-trip integrity tests
  integration.test.ts  Full pipeline tests

Related Projects

• Valkyrie - Scenario builder and player
• valkyrie-questdata - Community scenario source data
• valkyrie-store - Scenario manifest pipeline

License

MIT