Play D&D with Gemini in Foundry VTT.

Can Gemini run your Foundry game?

Yes. Gemini drives Familiar, the Foundry module that puts an AI on the dungeon master's side of the table. You ask in plain language and it acts in your world: it rolls initiative, plays the monsters, looks up a rule, voices an NPC, and keeps a record of the campaign. You stay the player.

How well it plays comes down to what you feed it. Gemini does not invent your campaign. You import a published adventure, the maps someone painted and the NPCs someone wrote, and it reads that work and runs the table on it, from a single scene to a whole campaign. The story stays the one you brought.

Gemini runs the adventure you imported. It does not improvise a plot from nothing, which is the line between Familiar and a weekend AI-DM app.

• New here? Start with adding AI to FoundryInstall Familiar and connect your first model.

Connecting Gemini to Foundry

Gemini connects two ways, and neither is a "Gemini app", because there is no standalone Gemini MCP client the way Claude has one. The first route is over MCP through Antigravity, the agent Google ships. You sign into Antigravity with a Google account and it speaks the Model Context Protocol to Familiar. A free Google account works here, so this is the one path in the three big assistants that needs no paid plan at all.

The second route skips the agent entirely: paste a Google API key into Familiar's built-in chat and it runs a Gemini model directly from Foundry's sidebar. That is the simplest setup, and it is billed per token. Familiar's wizard writes the Antigravity config for you; the built-in-chat key is a paste-and-go. The click-by-click for both lives in the connect guide.

• Over MCP: Antigravity CLI or the Antigravity Editor, signed in with Google. A free account is enough.
• By API key: paste a Google key into the built-in chat to run a Gemini model directly.

• Connect over MCP: the step-by-stepPer-client setup for Antigravity, and the built-in-chat key.
• MCP vs API: which to chooseThe subscription route versus a Google API key.

Playing D&D with Gemini

However you connected, you play by talking to your game. Ask Gemini to open the scene, run the fight, or remind you what happened last week. It reads the situation, calls the Familiar tools, and the canvas responds: a token slides into place, a condition lights up, the journal jumps to the page.

The dice live in code Gemini never touches, so it cannot fudge a roll; the voice and the read on a ruling are Gemini's.

The reasoning dial differs by model, so how hard Gemini thinks is worth a look before a fiddly night. Over MCP your Antigravity client sets that; on a Google API key you set it in Familiar. Which model, and how hard to let it think, is its own guide.

• Combat & AI
• Journals & Notes

• Choosing an AI model, and how hard it thinksTiers, the Thinking dial, and where the model shows up.

Connect Gemini and play

Install Familiar in Foundry, connect Gemini through Antigravity or paste a Google key, and import the first chapter of a published adventure you own. That is enough to run a session and see how it feels.

• Install Familiar in Foundry
• Connect Gemini over MCP
• MCP vs API: which to choose
• Questions? Ask in the Discord