Dice, characters, NPCs, encounters, loot, and the full 5e SRD reference — monsters, spells, equipment, classes, races, conditions, magic items. Build a character, stat an encounter, resolve the rolls, and look up every rule without leaving the cluster.

Pricing: pay-per-call in USDC on Base. No subscriptions, no API keys. See per-tool prices below.

Install — Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "agentutility-rollforge": {
      "command": "npx",
      "args": ["-y", "@agentutility/mcp-rollforge"],
      "env": { "X402_PRIVATE_KEY": "0xYOUR_PRIVATE_KEY_HEX" }
    }
  }
}

Restart Claude Desktop. 26 tools appear in the tool palette.

Install — Cursor

Add to .cursor/mcp.json:

{
  "mcpServers": {
    "agentutility-rollforge": {
      "command": "npx",
      "args": ["-y", "@agentutility/mcp-rollforge"],
      "env": { "X402_PRIVATE_KEY": "0x..." }
    }
  }
}

Funding

Send any amount of USDC on Base mainnet to the address derived from your X402_PRIVATE_KEY. The MCP server uses it to pay for tool calls automatically.

USDC on Base contract: 0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913

Tools (26)

Tool	Description
`ability-check`	(0.005 USDC/call) Resolves a d20 ability check, skill check, attack roll, or saving throw for tabletop RPGs. Rolls a d20 with an optional modifier and advantage/disadvantage, compares to a DC, and reports total, success/failure, and natural-20 / natural-1. Seedable. Use it as a d20 check resolver API for any RPG.
`background-gen`	(0.005 USDC/call) Character background generator API / personality trait, ideal, bond, flaw generator for tabletop RPGs. Rolls the four roleplaying hooks for a character sheet — a personality trait, an ideal, a bond, and a flaw. Seedable. Original generic-fantasy phrasing.
`character-gen`	(0.005 USDC/call) Generates a complete D&D 5e-style character, from ability scores to a procedurally generated name. Rolls ability scores (4d6-keep-highest-3, 3d6, or standard array) assigned by class priority, plus race / class / background / alignment, racial ability bonuses, derived hit points, ability modifiers, proficiency bonus, and saving-throw proficiencies. Pin any field (race, class, level 1-20, method, name) or omit to randomize; pass 'seed' for a reproducible character. Uses only 5e SRD content (OGL 1.0a / CC-BY-4.0). Use it as a tabletop character generator API, RPG character creator, or random fantasy character builder.
`character-portrait`	(0.08 USDC/call) Generates an RPG character portrait from structured inputs and returns a hosted PNG URL. Builds the image from race, class, gender, a free-text description, and an art style (fantasy-art, realistic, anime, oil-painting, ink-sketch, watercolor, pixel-art, comic-book). Pairs with character-gen: generate the character, then its portrait. Text-to-image via Venice, output hosted on fal. Use it as a character portrait generator API, RPG character art source, D&D character image maker, or fantasy avatar generator.
`class-lookup`	(0.003 USDC/call) Looks up a D&D 5e class by name for its SRD reference details. Returns hit dice, armor/weapon/tool/skill proficiencies, saving throws, spellcasting ability, and starting equipment; or list all SRD classes. SRD content only (OGL 1.0a / CC-BY-4.0). Use it as a class lookup API or class proficiencies and hit dice reference.
`condition-lookup`	(0.003 USDC/call) D&D 5e condition lookup API / SRD conditions reference (blinded, grappled, prone, stunned, etc.). Look up a condition by name for its full rules text, or list all SRD conditions. SRD content only (OGL 1.0a / CC-BY-4.0).
`dice-roll`	(0.005 USDC/call) Rolls dice from standard dice notation for tabletop RPGs. Evaluates XdY, flat modifiers (+/-), and keep-highest / keep-lowest (4d6kh3 for stat rolls, 2d20kh1 / 2d20kl1 for advantage/disadvantage). Returns each individual die, which were kept vs dropped, the per-roll total, and the grand total; roll the whole expression up to 100 times with 'rolls'. Pass 'seed' for reproducible output. Use it as a dice roller API, dice notation evaluator, or tabletop random roll engine.
`dice-stats`	(0.005 USDC/call) Calculates the probability distribution of a dice roll, anydice-style. For plain XdY+mod returns the EXACT distribution (mean, stdev, min, max, and P(>= target)); for keep-highest/lowest (4d6kh3, 2d20kl1) estimates via seeded Monte Carlo. For sizing DCs, damage, and stat rolls. Use it as a dice probability calculator API, dice statistics tool, or odds-of-a-dice-roll checker.
`dungeon-room`	(0.005 USDC/call) Generates a random dungeon room for game masters: shape, contents, a notable feature, a hazard, an occupant, and the number of exits. Pass 'rooms' for a small batch. Seedable. Use it as a dungeon room generator API, random dungeon generator, or D&D room description source.
`encounter-builder`	(0.005 USDC/call) Encounter builder / encounter difficulty calculator API for D&D 5e. Give the party (levels, or size + level) to get easy/medium/hard/deadly XP thresholds; optionally give monster CRs to get the multiplier-adjusted XP and the resulting difficulty rating. SRD DMG tables (OGL 1.0a / CC-BY-4.0).
`equipment-lookup`	(0.003 USDC/call) Looks up D&D 5e weapons and armor from the SRD by name. Returns weapon damage dice/type/properties/cost, or armor class/cost/weight/stealth; or list items by type ('weapon' or 'armor'). SRD content only (OGL 1.0a / CC-BY-4.0). Use it as an equipment lookup API or gear stats reference.
`initiative-roll`	(0.005 USDC/call) Initiative tracker / initiative order roller API for tabletop combat. Each combatant rolls 1d20 plus their initiative (DEX) modifier; returns the full turn order, ties broken by modifier then input order. Seedable.
`loot-gen`	(0.005 USDC/call) Loot generator / treasure generator API for D&D 5e. Rolls coins (and, for hoards, gems/art objects and a magic-item slot) scaled by a challenge-rating band. SRD-style treasure math (OGL 1.0a / CC-BY-4.0). Seedable.
`magic-item-lookup`	(0.003 USDC/call) Looks up a D&D 5e magic item by name from the SRD. Returns type, rarity, attunement, and full description; or list items filtered by rarity and/or type. SRD content only (OGL 1.0a / CC-BY-4.0). Use it as a magic item lookup API, SRD magic items search, or wondrous item reference.
`monster-lookup`	(0.003 USDC/call) Looks up a D&D 5e monster by name and returns a compact SRD stat block. Includes size, type, alignment, AC, HP, hit dice, speed, ability scores, challenge rating, and actions; or list monsters filtered by challenge rating and/or type. SRD content only (OGL 1.0a / CC-BY-4.0). Use it as a monster lookup API, SRD monster stat block source, or bestiary search.
`name-gen`	(0.005 USDC/call) Generates original fantasy names for RPG characters and NPCs, optionally flavored by race (Dwarf, Elf, Half-Orc, etc.). Names are original and syllable-built. Batch up to 50 at once with 'count'; pass 'seed' for reproducible output. Use it as a fantasy name generator API, RPG name generator, or a source of random D&D character and NPC names by race.
`npc-gen`	(0.005 USDC/call) Generates a quick NPC for game masters: name, race, occupation, personality trait, distinctive appearance, mannerism, and a hidden secret/plot hook. Pin race or occupation, or omit to randomize. Seedable. Use it as an NPC generator API, random D&D NPC, or tabletop character generator for GMs.
`quest-gen`	(0.005 USDC/call) Generates a random quest hook for tabletop adventures: giver, objective, location, complication, and reward, plus a one-line ready-to-read hook. Seedable. Original generic-fantasy content. Use it as a quest generator API, random plot hook, or D&D adventure seed generator.
`race-lookup`	(0.003 USDC/call) Looks up a D&D 5e race by name for its SRD racial traits. Returns ability score increases, speed, size, languages, vision, and racial traits; or list all SRD races. SRD content only (OGL 1.0a / CC-BY-4.0). Use it as a race lookup API or racial traits and ability score increases reference.
`random-table`	(0.005 USDC/call) Rolls on any custom random table you provide, with optional weights or classic die ranges. Accepts weighted entries ([{value, weight?}]) or die-range rows ([{min,max,result}] with a 'die'), any number of times, with or without replacement. Seedable. A generic random-selection utility for any custom table. Use it as a random table roller API, weighted random picker, or loot and rumor table roller.
`settlement-gen`	(0.005 USDC/call) Generates a random fantasy settlement: name, size category with a plausible population, government, primary trade, a notable feature, and a current problem the party could engage with. Pin 'size' (hamlet/village/town/city) or randomize. Seedable. Use it as a settlement generator API, random town generator, or D&D village and city generator.
`spell-lookup`	(0.003 USDC/call) Looks up a D&D 5e spell by name and returns full SRD details. Includes level, school, casting time, range, components, duration, concentration, ritual, classes, description, and higher-level scaling; or list spells filtered by level and/or school. SRD content only (OGL 1.0a / CC-BY-4.0). Use it as a spell lookup API, SRD spell search, or spell card details source.
`spell-slots`	(0.005 USDC/call) Looks up D&D 5e spell slots by class and level. Returns the level 1-9 spell-slot array for any 5e class at a given level (full casters, half-casters like Paladin/Ranger, Warlock pact magic, and non-casters), plus proficiency bonus. SRD spellcasting tables (OGL 1.0a / CC-BY-4.0). Use it as a spellcasting slot table API or pact magic lookup.
`tavern-gen`	(0.005 USDC/call) Generates a random fantasy tavern: name, proprietor, the house drink and meal, a notable patron, and a rumor overheard inside. Seedable. Original generic-fantasy content. Use it as a tavern generator API, random fantasy inn, or D&D tavern name and details source.
`weather-gen`	(0.005 USDC/call) Rolls a day's weather for a fantasy RPG campaign by climate (temperate, arid, cold, tropical), with conditions and wind. Pass 'days' for a short forecast. Seedable. Use it as a fantasy weather generator API, random RPG weather source, or tabletop campaign weather forecast.
`xp-level`	(0.005 USDC/call) Converts between XP and level using the D&D 5e experience table. Give 'xp' to get the current level, XP to the next level, and progress; or give 'level' to get the XP needed to reach it. Returns proficiency bonus. SRD advancement table (OGL/CC). Use it as an XP to level calculator or level from XP lookup API.

How it works

Agent calls a tool (e.g. ability-check).
MCP server POSTs to https://x402.agentutility.ai/ability-check.
The endpoint responds HTTP 402 with payment instructions.
The MCP server signs an EIP-3009 USDC transfer authorization with X402_PRIVATE_KEY and retries.
CDP facilitator settles on Base.
The endpoint returns the actual response.

The agent never sees the payment flow — it just gets the result.