How to add AI to Foundry VTT.

What "AI in Foundry" actually means

Familiar is a Foundry module that puts an AI on the DM's side of the table. You talk to it in plain language and it does the work a GM would otherwise do by hand: it rolls initiative, runs the monsters, looks up a rule, voices an NPC, keeps a record of the campaign. You stay in the scene instead of digging through menus.

Set the expectation before you install: it comes down to what you give it. Ask an AI to invent a campaign from nothing and it drifts. Give it a full published adventure, the maps someone painted, the NPCs someone wrote, the statblocks and journals you imported, and it has real material to run. It reads that work and runs the table on it, from a single scene to an entire campaign. It never invents the story. That part stays yours.

This is the line between Familiar and a weekend AI-DM app: it runs the adventure you imported, it does not improvise one.

What you need

Four things, and you likely have most of them already.

• Foundry VTT on v13 or later, with a world you run as GM.
• The Familiar module, installed and enabled in that world. The install steps are below.
• A published adventure to import, so the AI has maps, NPCs, and statblocks to run from. D&D 5e (2024) also gets the rules engine; on other Foundry systems everything else still runs, and your own system keeps the rules.
• An AI to drive it. Connect a Claude, ChatGPT, or Gemini subscription over MCP, or paste an API key from a supported provider into the built-in chat.

• Not playing D&D 5e?What runs on your system, and the one part that is 5e only.

Add AI to Foundry in three steps

Three steps, and the first is the same as installing any other Foundry module. The detail for each is further down; this is the whole shape.

1. 1

   Install Familiar

   Search for Familiar in Foundry's package browser and install it, or paste the manifest URL. Either way it is the standard module install. The click-by-click is below.

2. 2

   Connect the AI you already use

   Open Familiar's settings and connect a model. Two paths: drive it from a Claude, ChatGPT, or Gemini subscription you already pay for, or paste an API key. The keys are yours and the cost is yours.

3. 3

   Import an adventure and play

   Bring a published adventure into your world so the AI has journals, sheets, and statblocks to run from. Then start a session and talk to your game.

Install Familiar in Foundry

Familiar installs the way every Foundry module does, through the Add-on Modules dialog. It is listed in the official Foundry package directory, so the quickest route is to search for it.

In Foundry, open Add-on Modules, click Install Module, search Familiar, and click Install. Then enable it in the world where you run your game. That is the whole module setup.

If you would rather paste it in, the manifest URL installs the same release from the same dialog:

https://github.com/Ryanjansen92/familiar-releases/releases/latest/download/module.json

Connect your AI: two paths

Familiar is bring-your-own-AI. It ships no model and never proxies your tokens, so you point it at one you control. Pick the path that matches what you already pay for.

Most GMs already hold one of these. A Claude, ChatGPT, or Gemini subscription drives the game over MCP with no extra API bill. Or paste a key and start typing: the built-in chat takes an API key from any supported provider and runs in Foundry's sidebar, with a few conveniences like live transcription on top.

• Use your subscription (MCP). Connect over the Model Context Protocol so your existing Claude, ChatGPT, or Gemini plan drives the game at no extra API cost (ChatGPT connects through Codex). Best for long, multi-step turns.
• Paste an API key (built-in chat). Pick a provider, paste a key, and talk to your game from Foundry's sidebar. No terminal, no config. It is also the only route to a model on your own machine, through the Local AI tab. Live transcription lives here only; voice and image generation work on either path.

Not sure which fits? The MCP vs API guide lays the two side by side, with the numbers for how your table actually plays.

What it costs to run

Two costs, and they are separate. Familiar itself is $5 a month, or $45 a year, with the first 14 days free. That keeps the module maintained and every update included.

The AI is the other cost, and it is yours directly. Familiar never marks up or proxies tokens. On the subscription path there is no per-token bill at all: you spend the Claude, ChatGPT, or Gemini plan you already hold. On an API key, your provider bills you for what you use, roughly $0.50 to $3 for a session depending on the model. A model you run on your own machine costs nothing per token.

• Running a local AI modelThe route with no token bill, and what your PC needs for it.

What it does once connected

With a model connected and an adventure imported, you run the game by talking to it. Ask for what you want and it acts in Foundry, without breaking the scene to click through menus. These are shipped capabilities, mapped to what they do at the table.

• Combat bookkeeping. Roll initiative, resolve attacks and saves, apply conditions and damage, track death saves, and play the monsters' turns from their real statblocks, so a fight never stalls on the maths.
• Journal and rules lookup. Full-text search across every journal, character, scene, and item, so when a name or a 5e rule comes up the AI reads the actual entry instead of reaching for whatever sounds right.
• NPC voices. Anchor an NPC to a written character and the AI speaks them in their own assigned voice, holding to what their sheet says rather than improvising a new backstory.
• Prep support. The AI reads the journals and statblocks you imported at the table, so the prep you built is what it runs from, not a guess.
• Cross-session memory. A persistent record of your campaign plus a rewritten plot summary carry from one session to the next, so what was true last week is still true tonight.

• Combat & AI
• Journals & Notes
• Voice & Image Generation
• Knowledge & Memory

Play solo, one-on-one, or a full table

How much of the table the AI runs comes down to how many humans are at it. At a full table it is your co-pilot: it takes the bookkeeping and the monsters so you can run the story for everyone else. The fewer players, the more it runs.

Import a full published campaign, its maps, characters, NPCs, and statblocks, and the AI can run the whole DM's side of it around a single player. That is what makes solo and one-on-one play work: you finally play a module you own, instead of only ever running it for other people. The more complete the import, the more the AI can run, so a fully prepared campaign is where solo play holds together best.

What stays yours, and what it will not do

Familiar runs the DM's side of the table: the rules, the dice, the monsters, the cast you wrote, and the recall. The story it tells is the one you brought. You hold the spine.

And the world you brought stays the work of the people who made it. Someone hand-painted that battlemap and placed every wall, light, and ambient track on it. Someone spent months on the adventure it belongs to. Familiar reads that craft and runs the table on top of it; it does not redraw the map or rewrite the module. When it does generate, a quick NPC portrait or a line read in a voice, that is for a gap you have not filled, never a re-render of what a creator already made.

It keeps no secrets from you. Hidden information is Foundry's own fog of war and dice-gated reveals, not an AI deciding what to withhold. And it takes an ally's turn beside you: a friendly NPC you own, run on the combat auto-pilot like a monster, or a party character you hand it to play.

The trade is deliberate, and it is the honest one. Give it good prep and it runs the mechanics and the cast reliably, anchored to what you built. It fills the small edges itself. Hand it a character you invented and it plays that too, as long as you wrote them down first. What it will not do is author the plot from nothing: the spine is the published campaign you brought. Build that base in a prep session, not mid-game, and it improvises the rest around it.

Familiar and Foundry's AI policy

Foundry takes AI seriously enough to publish a content policy, and this community is protective of the human work its worlds are built from. Familiar is listed in the official Foundry directory, declared as shipping zero AI-generated content. It is a tool that runs the content you own, not a generator that fills a directory with machine-made assets to sell.

What it makes, a portrait or a spoken line, stays at your table for that session, not something it packages up to sell. Familiar earns a seat beside the work you brought; it does not stand in for it.

Add it to your next session

You do not need a full campaign prepped to start. Install Familiar, connect the AI you already pay for, and import the first chapter of a published adventure you own. That is enough to run a session and see how it feels.

From there, these cover playing it well:

• How to play D&D with AIGood AI D&D is good prep, then hand the running over.
• Prepping a published adventureLay an adventure into Foundry so the AI reads it cleanly.
• Playing solo and duetRun a module's DM side around a single character.