Most campaign managers store text. Grimoire stores state: the queryable truth of your
world that your AI assistant, your players, and future-you all draw from. Build your
bible once. Track every thread. Enforce every homebrew rule. Run sessions out of
structured memory instead of scattered Google Docs.
Free tier includes the full builder. No credit card. MCP included.
The wedge
A wiki remembers pages. A campaign manager remembers state.
A D&D campaign isn't a document. It's a live system of NPCs with motivations, factions
with loyalties, plot threads that haven't resolved, secrets the party hasn't learned, and
rules that override the rulebook. Most tools treat your campaign as text: pages you write,
pages you re-read, pages you forget you wrote. Grimoire treats it as state: typed entities
with relationships, threads that progress between sessions, canon facts your AI assistant
can query but can't contradict.
The difference shows up in three places.
Ask what's open right now and a wiki searches text.
Grimoire returns open threads sorted by recency, with the sessions they were introduced
in and the entities they touch.
A player asks what do we know about House Vale and a
wiki shows everything you wrote. Grimoire shows only the player-knowledge tier. The GM
secrets stay GM secrets, automatically.
Your AI assistant asks how would Queen Mira react to her
brother's betrayal and a wiki has nothing to hand it. Grimoire hands it Mira's
motivations, her established history with Cyrus, the political web she sits in, and the
visibility rules. The AI answers in your canon, not generic fantasy.
This page walks through how that works, concretely, for a campaign you'd actually run.
The four pieces
What Grimoire tracks that your wiki doesn't.
Four components make up a campaign's state. Each is queryable from any AI assistant
connected via MCP, and each updates as you play.
Constitution
The world truths
The bedrock rules your AI assistant defers to before it answers. Magic system, cosmology, pantheon, founding events, custom mechanics, the things that are different here than in the rulebook. Decide magic doesn't work underwater in your campaign and the Constitution says so. Decide Tyr is dead and Helm took his domain and the Constitution remembers. The AI reads it first, every query.
"Magic disrupts in the storm-touched seas. Spells with verbal components fail above the waves; spells with somatic components fail below them. This overrides RAW."
Entities
The cast and the world
Fourteen typed entity types: NPCs, Locations, Factions, Quests, Items, Vehicles, Creatures, Lore Entries, World Rules, Planar Forces, Session Recaps, Session Preps, Custom Mechanics, Player Characters. Each has structured fields (motivations, relationships, secrets, visibility tier) because most NPCs need them. Connect entities into knowledge graphs (political, geographic, timeline, custom) that render the same data through different lenses.
Eldric the Innkeeper. NPC at The Crooked Spire, Greyhaven. Independent publicly, House Vale informant in secret. Motivation: pay off his gambling debts. Met the party in session 4. Linked thread: "Vale debt" (open).
Open threads
The plot in motion
Threads track what is unresolved. The cult is planning something nobody knows about. The queen is sick and the succession is contested. House Vale needs an heir before the equinox. Each thread carries introduction context, progression notes, and the entities it touches. The AI can answer "what's open right now" or "what threads involve House Vale" without you searching your notes.
Thread: "Queen Mira's succession crisis." Open, introduced session 2. Touches Mira, Cyrus, House Vale, the Crown faction, the Greyhaven throne room. Last progression, session 7: Cyrus publicly denied any claim, privately met a House Vale envoy.
Narrative state
What just happened, what is true now
The narrative state aggregates the live snapshot: recent sessions in order, currently active arcs, canon facts established in play that weren't in your original notes. When a player asks "what did we learn last session" or your AI asks "what's the current situation," the narrative state is the answer. It persists across sessions and survives chat compactions. The next conversation picks up where the canon is, not where the last chat ended.
get_narrative_state -> Recent sessions: 7, 6, 5. Active arcs: Vale succession, the Cult of the Drowned Star, the missing caravan. Canon (player-knowledge): Cyrus denied his claim. Canon (GM-secret): Cyrus is the cult's silent backer.
Why this matters
Your homebrew is canon. Make the AI respect it.
Every D&D table runs homebrew. House rules. Custom monsters. A campaign-specific
pantheon. A magic system that diverges from the PHB on purpose. A retconned event the
players actually experienced differently than you originally wrote it. Generic AI
assistants know none of it. They pull from training data (the rulebooks, the SRD, the
Forgotten Realms wiki) and the answer you get is the answer for someone else's game.
Grimoire's Constitution, World Rules, and Custom Mechanics tell the AI what is true in
this specific world. Before any query, the AI reads them. Before any generated NPC
reaction, the AI defers to them. The setting rules win.
The pantheon question
Who is the god of war in this setting?
Generic AI
In the Forgotten Realms, Tempus is the god of war and battle. He is depicted as a...
AI with Grimoire MCP
In your setting, Tempus was deposed during the Sundering. The current god of war is Helm, who inherited the war domain when Tyr fell. (Source: Constitution, World Rules. Established in the session 1 lore dump.)
The mechanic question
Player rolled a natural 20 on a crit. What's the damage?
Generic AI
On a critical hit, you roll all damage dice twice and add modifiers once. So if the weapon is 1d8+3...
AI with Grimoire MCP
In your setting, crits restore HP equal to the rolled damage instead of dealing it, your custom mechanic from session 0. Roll 1d8 normally and the target heals that much. (Source: Custom Mechanics, "Crit-as-Heal.")
The character history question
How would Queen Mira react if Cyrus betrayed her?
Generic AI
A queen betrayed by her brother would likely feel a mix of grief and anger, torn between family loyalty and the demands of the crown...
AI with Grimoire MCP
Mira already suspects Cyrus is the cult's backer (GM-secret) and publicly denied his succession claim in session 7. Her reaction wouldn't be surprise, it would be the confirmation she has been waiting for. She moves on the cult immediately and uses the Crown's evidence-laundering channel through House Vale. (Source: NPC Mira, motivations plus active arc "Vale succession.")
How you actually use it
The four-part build cycle.
A homebrew D&D campaign builds in four passes. Each pass adds state the next pass and
the AI assistant draw on.
1
Build the Constitution
Spend twenty minutes on the rules of your world. What does magic do here that it doesn't do in the PHB? Who are the gods, and which ones are dead? Is there a real Astral Sea, are planes accessible, do gods speak directly? Any custom mechanics like initiative variants, alternate crits, or fatigue rules?
This becomes the AI assistant's source of truth. Skip it and the AI defaults to RAW. Fill it once and every future query respects your homebrew.
2
Seed the world
Add your starting cast. Five NPCs the players will meet in the first three sessions. Two or three factions in conflict. The town the campaign starts in, plus three locations in walking distance. The overarching mystery or threat, the thing the campaign is about.
The pre-built schema means you don't design fields. NPCs already have motivations, relationships, secrets, and a visibility tier. Factions have goals and rivals. Fill the boxes; the structure is done.
3
Run sessions, track state
Play your game. After or during each session, update the state. What threads opened? What threads progressed? What changed in the political picture? What did the players figure out, and what is still GM-secret?
Three minutes per session is enough. Or let your AI assistant do it with you: paste session notes into Claude or ChatGPT with Grimoire MCP connected, ask it to update entities and threads, and review the diffs.
4
Prep the next session from the state
When it is time to prep, query the state. What is open? What is the current situation? What did the players learn last session? Generate three rumors that fit your current city. Project what House Vale does next given their motivations and the events of session 7.
The AI prep gets better every session because the state has more in it. Most GMs feel the inflection point around session 4.
The AI part
Optional. Powerful. Free to try.
Grimoire is a complete campaign builder without a single AI feature turned on. The
Constitution, entities, threads, knowledge graphs, wiki, and player portal all work
standalone. You can run a five-year campaign in Grimoire without ever connecting an AI
assistant.
The AI part is opt-in via Grimoire MCP, a
one-OAuth-click integration with any MCP-compatible AI client (Claude.ai, Claude Desktop,
ChatGPT, Cursor). Once connected, the AI assistant reads your campaign state on every
relevant query. It also writes back, creating NPCs, updating threads, and recording session
canon directly through MCP tools. You stay the GM. The AI is the assistant.
You pick the model
Claude, GPT, Gemini, whatever ships next. Grimoire doesn't lock you to one model that ages out.
No token markup
You pay your AI client directly. Grimoire never charges for AI tokens. Free tier of Claude or ChatGPT plus free tier of Grimoire is end-to-end free to try.
Switch anytime
Don't like your client? Connect a different one tomorrow. Your campaign doesn't move. Your state doesn't re-sync.
Canon enforcement, not generation
Other AI-TTRPG tools generate characters or narrate the game. Grimoire makes sure the AI respects the characters and the game you already built.
Most homebrew GMs running one campaign never need to upgrade. The free tier is the product,
not a teaser.
Questions, answered
What people ask about the builder.
Is Grimoire a D&D campaign builder or a campaign manager?
Loosely, a builder is what you use to set up a campaign and a manager is what you use to run it. Grimoire is both, and uses the same data model for each. The world rules and entities you build in setup become the queryable state you manage during play. Splitting them into two tools means duplicating data across surfaces. Grimoire keeps the build and the run in one place.
What is a "Constitution" in Grimoire?
The Constitution is where Grimoire keeps the world truths your AI assistant should defer to: your magic system's rules, your cosmology, your custom mechanics, your retconned canon. Anything you'd answer "actually, in my setting..." about. The AI reads the Constitution first on every query and treats those rules as authoritative over generic D&D defaults.
How is this different from a wiki or Notion?
Wikis and Notion store text. Grimoire stores typed state. NPCs aren't pages, they're entities with structured motivations, relationships, secrets, and visibility tiers, queryable through knowledge graphs. The wiki layer is still there for free-form notes, but the durable layer is the typed entities. Practical difference: in a wiki you find things by searching text. In Grimoire you query: every NPC tied to House Vale, every open thread that touches Greyhaven, every secret the players don't know about Cyrus. The query is the workflow.
Can I use Grimoire without AI?
Yes. The full builder works without any AI integration. Most of Grimoire's value (typed entities, knowledge graphs, player portal, real-time collaborative wiki) has nothing to do with AI. Grimoire MCP is an opt-in layer for GMs who already use Claude, ChatGPT, or another AI assistant for prep. The product is honest about which features need AI and which don't.
What does the AI workflow actually look like?
Three concrete examples. One: you paste a paragraph of session notes into Claude with Grimoire MCP connected and ask it to parse them into typed entities. It creates the NPCs, links them to factions, opens the threads, all live. Two: mid-prep you ask "what's open right now in my campaign" and the AI answers from get_narrative_state without you re-explaining anything. Three: you ask "how would Queen Mira react to her brother's betrayal" and the AI grounds its answer in Mira's actual motivations and the political web she sits in, not generic queen-betrayed-by-brother tropes.
Do I need to know what "narrative state" means to use Grimoire?
No. The phrase is a way of describing what Grimoire does under the hood. In practice you click "create NPC," fill in motivations and relationships, and play your game. The state grows naturally as you add entities and update threads. The phrase matters most if you connect an AI assistant, because that's when "queryable state" becomes a tangible product feature.
Is Grimoire only for D&D?
No. Most of Grimoire's tooling is system-agnostic. The 14-entity schema fits D&D 5e most natively, but it works for Pathfinder, Call of Cthulhu, Blades in the Dark, Vampire, and homebrew systems. The Constitution and Custom Mechanics entities are explicitly designed for whatever rules you're running.
How long does it take to build a campaign in Grimoire?
A session-ready skeleton takes 20 to 45 minutes for most GMs. The schema is pre-built, so you fill structured fields rather than design hierarchy, and most of the time goes to the creative work (who your NPCs are, what your factions want) rather than tool setup. The MCP-assisted path is faster: paste half-formed notes into Claude or ChatGPT and let the AI parse them into typed entities, then review and clean up.
What happens to my data if I cancel?
You keep export access. Grimoire's free tier never expires, so most GMs who downgrade from Pro just go back to Free with one full campaign intact. Pro users get full data export to JSON before any plan change. We don't hold your campaign hostage.
Can my players see what I am building?
Only what you let them see. Every entity has a visibility tier: common knowledge (everyone sees), player knowledge (players see, with invite), GM secret (only you). Player auth is a separate tier with invite-code login, and players see a portal scoped to permitted entities. GM secrets stay GM secrets even when a player is the one querying your AI assistant.
A D&D campaign that thinks. Free to start.
The Constitution. The entities. The knowledge graphs. The narrative state. The MCP-native
AI integration. All on the free tier. One campaign, unlimited entities, forever, no card.