2D6 MCP — AI GM Assistant

SPDX-License-Identifier: AGPL-3.0-only Copyright (C) 2026 Jupiter Industries (Liam Crowter) and the 2d6mcp maintainers

A system-agnostic Model Context Protocol (MCP) server and hosted Cloudflare Worker providing a mechanical engine, dice roller, rules reference, and AI-powered rulings assistant for tabletop RPGs. Supports sci-fi (OGL/Cepheus Engine SRD), fantasy (Dungeon World, CC-BY-3.0), generic percentile (Basic Roleplaying SRD, BRP OGL v1.0), and d20 fantasy (5E-compatible SRD, CC-BY-4.0) games.

Deployment Modes

Mode	Description	Cost
Self-Hosted MCP Server	Run locally on your machine. Full BYOD support, MLX-powered audio transcription and ruling synthesis (macOS). Works in any AI harness (Claude, Kilo, Cursor, etc.)	Free (AGPL-3.0)
Hosted Discord Bot	Deploy to Cloudflare Workers. Discord slash commands, Workers AI-powered rulings (Qwen3 MoE), web dashboard. Zero local setup beyond wrangler.	Free (self-deploy, AGPL-3.0)

Features

• Dice Engine — 2d6+1, 3d6, d66, target numbers, effect margins
• OGL Rules Database — Generated on first use from bundled seed data: Cepheus Engine SRD (OGL v1.0a)
• Dungeon World Database — Generated on first use from bundled seed data: moves, classes, spells, monsters, GM tools (CC-BY-3.0)
• Basic Roleplaying Database — Generated on first use from bundled seed data: BRP SRD 1.0.2 characteristics, skills, professions, weapons, armor, spot rules (BRP OGL v1.0)
• 5E-Compatible Database — Generated on first use from bundled seed data: d20 fantasy SRD classes, spells, monsters, feats, and rules (CC-BY-4.0)
• AI Rulings — Ask rules questions, get cited answers from OGL/DW/BRP/5E-compatible/BYOD sources. Powered by Qwen3 MoE (Cloudflare) or MLX LLM (self-hosted)
• Discord Bot — Slash commands (/ask, /roll, /session) in your TTRPG server. Real-time rulings with source citations
• BYOD Indexing — Ingest your own PDF/text/markdown files for local full-text search (self-hosted only)
• Session Management — Start/end sessions, log transcripts, search what was said at the table
• Cross-Platform AI — Cloudflare Workers AI (Whisper + LLM) works on any device, no GPU needed

Quick Start — Self-Hosted MCP Server

git clone https://github.com/crowterliam/2d6mcp.git
cd 2d6mcp
npm install
npm run build
npm run setup          # create consent token for BYOD mode
npm run populate-ogl   # generate the OGL rules database
npm run populate-dw    # generate the Dungeon World rules database
npm run populate-brp   # generate the Basic Roleplaying rules database
npm run populate-5ecompatible  # generate the 5E-compatible rules database
npm run start          # run the MCP server (stdio transport)

Quick Start — Hosted Discord Bot (Cloudflare)

git clone https://github.com/crowterliam/2d6mcp.git
cd 2d6mcp
npm install
npm run setup-cloud

The interactive wizard guides you through:

• Cloudflare login + account setup
• Discord bot token + configuration
• Worker deployment, D1 + R2 creation, rule seeding
• Slash command registration

5 minutes, one command. Then paste the Interactions Endpoint URL in Discord Developer Portal.

MCP Client Configuration

{
  "mcpServers": {
    "2d6mcp": {
      "command": "node",
      "args": ["/absolute/path/to/2d6mcp/packages/server/dist/index.js"],
      "env": {
        "AGREE_BYOD_USE": "true",
        "BYOD_PATH": "/path/to/your/rpg/files"
      }
    }
  }
}

BYOD — Non-Commercial Use Disclosure

BYOD (Bring Your Own Documents) mode enables local file ingestion for personal, non-commercial use only. By enabling BYOD (AGREE_BYOD_USE="true" or npm run setup), you confirm that:

• You are the legal owner of the imported files or hold a valid license to use them.
• This tool is provided strictly for personal, non-commercial automation and referencing.
• The developers of this software do not condone piracy or the unauthorized distribution of copyrighted tabletop roleplaying materials.

BYOD is self-hosted only and is not available in the hosted Cloudflare Worker.

Tools

MCP Server Tools (Self-Hosted)

Tool	Description
roll_2d6	Roll 2d6 with modifier, compare against target, return effect margin
roll_d20	Roll d20 with modifier, advantage/disadvantage, AC/DC comparison, critical hits and fumbles
roll_percentile	Roll d100 with BRP-style roll-under, critical success, and fumble detection
roll_damage	Roll damage dice with optional type ("2d6+3 fire", "1d8 piercing")
roll_custom	Roll any dice notation (3d6, 1d20, 4d6+2)
roll_table	Roll on a named table from any rules system (use system param)
query_ogl_rules	Search the OGL database for rules, skills, careers, equipment, or tables
query_dw_rules	Search the Dungeon World database for moves, classes, spells, equipment, monsters, GM tools
query_brp_rules	Search the Basic Roleplaying database for characteristics, skills, professions, weapons, armor, spot rules
query_5ecompatible_rules	Search the 5E-compatible database for spells, monsters, classes, feats, and rules
query_orcus_rules	Search the Orcus 4e-compatible database for classes, monsters, feats, and rules
query_local_byod	Search your locally ingested BYOD files (requires consent)
parse_character	Parse a character sheet file into structured JSON
sync_byod	Index/re-index all files in your BYOD directory
clear_byod	Delete the BYOD index to start fresh
list_byod_files	List all indexed files with chunk counts and status
inspect_byod_file	Show chunk structure for a specific indexed file
sync_file	Index a single file by relative path
get_byod_chunk	Retrieve full chunk content by file path + chunk index
synthesize_ruling	Synthesize a rules ruling using local MLX LLM with OGL/DW/BRP/5E-compatible/BYOD citations
resolve_from_context	Take recent session transcript, detect rules question, synthesize ruling
session_start	Start a new game session for transcript logging and rulings tracking
session_end	End the active game session
session_list	List all recorded game sessions
session_summarize	Generate an AI summary for a session via MLX LLM
log_transcript	Log a transcript segment to the current session
get_session_context	Get recent transcript segments and rulings
search_transcript	Full-text search across session transcripts
transcribe_audio	Transcribe an audio file using local MLX Whisper
list_transcriptions	List in-progress audio transcriptions
clear_transcription	Reset transcription progress
delete_session	Permanently delete a session and all its data
discord_post	Post messages to Discord webhooks with smart routing
discord_add_webhook	Add a Discord webhook with name, URL, tags
discord_remove_webhook	Remove a stored Discord webhook by name
discord_list_webhooks	List all configured webhooks
discord_test_webhook	Send a test message to verify webhook connectivity

Discord Bot Commands (Hosted)

Command	Description
/ask <question>	Ask a rules question — Workers AI Qwen3 MoE returns a cited ruling
/roll <notation>	Roll dice (2d6+1, 3d6, d66)
/session start <name>	Start a game session
/session end	End the current session
/session context [minutes]	View recent transcript and rulings
/search <query>	Search session transcript
/help	Show available commands

Architecture

2d6mcp/
├── apps/
│   ├── worker/          # Cloudflare Worker — API, Discord bot, Workers AI, D1, R2
│   ├── bridge/          # Discord voice relay (VPS — raw UDP required)
│   ├── web/             # Vite + React SPA dashboard + landing (Phase 3)
│   └── recorder/        # Browser PWA fallback audio capture (Phase 4)
├── packages/
│   ├── server/          # MCP server — stdio transport, local MLX, BYOD, session DB
│   ├── shared/          # @2d6mcp/shared — dice, keywords, prompts, quality filter
│   ├── ogl/             # @2d6mcp/ogl — OGL rules database + queries
│   ├── dw/              # @2d6mcp/dw — DW rules database + queries
│   ├── brp/             # @2d6mcp/brp — BRP rules database + queries
│   └── 5ecompatible/    # @2d6mcp/5ecompatible — 5E-compatible rules database + queries
├── data/                # SQLite databases (shared)
├── tests/               # Vitest test suite (270 tests)
├── tsconfig.base.json
└── package.json         # npm workspaces root

Deployment Model

                    CLOUDFLARE                         VPS (Hetzner, DO, etc.)
┌──────────────────────────────┐  ┌──────────────────────────────────────┐
│  API Worker (Hono)           │  │  Bridge (Node.js + systemd)           │
│  /api/interactions (Discord) │  │  Auto-joins voice channels            │
│  /api/ask (Qwen3 MoE)        │◄─│  Ring buffer → Worker /api/audio-ingest│
│  /api/roll (shared dice)     │  │  Health /push-to-ask HTTP endpoint     │
│  /api/auth/* (OAuth2+JWT)    │  └──────────────────────────────────────┘
│  D1 (rules) + R2 (audio)     │
└──────────────────────────────┘
         │
    Discord (slash commands live)

Agent Modes

This project includes AI agent instructions for common coding assistants. See .kilo/agent/ for domain-specific modes:

Agent File	Domain
.kilo/agent/2d6mcp.md	Master reference — all tools, workflows, environment vars
.kilo/agent/2d6mcp-task-resolution.md	Dice rolling, effect margins, difficulty, boon/bane
.kilo/agent/2d6mcp-rules-reference.md	Rules lookup, table rolling, OGL + BYOD search
.kilo/agent/2d6mcp-character-creation.md	UPP, characteristics, career paths, skills
.kilo/agent/2d6mcp-byod.md	BYOD sync, listing, inspection, troubleshooting

Slash commands are in .kilo/command/ for quick access to common operations.

Build & Test

npm install           # install all workspace dependencies
npm run build         # compile all packages (tsc --build)
npm test              # run 270 tests across 26 test files
npm run typecheck     # type-check without emitting
npm run start         # run the MCP server (packages/server/dist/index.js)

Environment Variables

Self-Hosted MCP Server

Variable	Default	Description
AGREE_BYOD_USE	"false"	Set to "true" to enable BYOD mode
BYOD_PATH	—	Path to directory containing local RPG source files
BYOD_CHUNK_SIZE	8000	Characters per chunk (500–50000)
BYOD_CHUNK_OVERLAP	400	Overlap between consecutive chunks
BYOD_MAX_FILES	2000	Maximum files to process per sync
BYOD_MAX_CHUNKS_PER_FILE	500	Maximum chunks from any single file
BYOD_SYNC_TIMEOUT_MS	15000	Milliseconds per sync batch
BYOD_CONTENT_CACHE_PATH	data/byod/content_cache.db	Shared content cache database
OGL_DB_PATH	data/ogl/cepheus.db	Path to custom OGL SQLite database
DW_DB_PATH	data/dw/dungeon-world.db	Path to custom DW SQLite database
BRP_DB_PATH	data/brp/basic-roleplaying.db	Path to custom BRP SQLite database
SR5E_DB_PATH	data/5ecompatible/5ecompatible-srd.db	Path to custom 5E-compatible SQLite database
ORCUS_DB_PATH	data/orcus/orcus.db	Path to custom Orcus SQLite database
MLX_WHISPER_MODEL	mlx-community/whisper-large-v3-turbo	MLX Whisper model
MLX_LLM_MODEL	mlx-community/Llama-3.2-3B-Instruct-4bit	MLX LLM model
SESSION_DB_PATH	~/.2d6mcp/sessions.db	Session database location
STT_BACKEND	mlx	STT backend: mlx or whispercpp
LLM_BACKEND	mlx	LLM backend: mlx or llamacpp

Hosted Cloudflare Worker

Variable	Set via	Description
DISCORD_BOT_TOKEN	wrangler secret put	Discord bot token
DISCORD_PUBLIC_KEY	wrangler secret put	Discord interactions public key
DISCORD_CLIENT_ID	wrangler secret put	Discord application client ID
DISCORD_CLIENT_SECRET	wrangler secret put	Discord OAuth2 client secret
JWT_SECRET	wrangler secret put	HMAC secret for user JWT tokens
API_URL	wrangler.toml	Worker base URL
WEB_URL	wrangler.toml	Web dashboard URL

License

This project uses a multi-license architecture:

• Source code (apps/**, packages/**, root config files): AGPL-3.0-only
• OGL game data (data/ogl/**): OGL v1.0a
• Dungeon World data (data/dw/**): CC-BY-3.0
• Basic Roleplaying data (data/brp/**): BRP Open Game License v1.0
• 5E-compatible SRD data (data/5ecompatible/**): CC-BY-4.0

The BRP logo (BRP.png in the project root and data/brp/BRP.png) is a trademark of Chaosium Inc., displayed in compliance with Section 15 of the BRP Open Game License v1.0.

You are granted permission to reproduce the logo only for the purpose of labeling derivative works under the BRP OGL.

Full license documentation: LICENSE.md

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Copyright © 2026 Jupiter Industries (Liam Crowter) and the 2d6mcp maintainers