Run D&D with AI, honestly.

Install Familiar, activate your licence key, then paste a provider key or connect a plan you already pay for. The on-ramp to an AI co-pilot in Foundry.

Point the Claude, ChatGPT, Gemini, or Grok you already use at your Foundry game over MCP and it runs the DM's side: the monsters' turns, the 5e rules, the NPCs in character. No model key to buy, no per-token bill.

Anthropic builds both clients, so no agent app sits in the path. Desktop and Code differ in how you add each one, how many tools each carries, and whether a fetched picture ever reaches your screen.

The Chat tab is not the piece that connects. The Codex tab in the ChatGPT app is, on every plan including Free, and so is Codex CLI from Plus upward: OpenAI's own agent either way. Both read the same config file.

Antigravity is Google's agent, and it is what reaches your Foundry game. Any Google account gets you in, including a free one. Or skip the agent altogether: a Google API key, pasted into Familiar's own chat window.

xAI's terminal agent is the one Grok that speaks to a Foundry game, on the SuperGrok plan you already pay for. One command registers Familiar, and grok mcp doctor familiar proves the link before you type a word. The Grok app itself cannot reach a server on your machine.

Subscription or API key? MCP subscription versus a pay-per-token key, and which is cheaper for how your table actually plays.

Which model, and how hard should it think? A capable model with reasoning headroom is the second lever behind good prep. Turn thinking up for fiddly rules, down to keep replies fast.

Run the model on your own PC instead of a provider, so your world never leaves the machine and the bill moves from a token meter to your graphics card. Setup is one settings tab and one switch. Without a discrete GPU, expect minutes per turn.

Good AI D&D is good prep. Structure a published adventure, then hand the running to the AI.

Lay a published adventure into Foundry as journals, sheets, and a one-page outline, so the AI has the pages to run from.

Your vault is never copied into Foundry: the AI reads it where it is, through Obsidian's community plugin. What the setup takes, what a note looks like once the AI reads it, and how to fence off the folders it should not see.

Give an NPC who they are, what they know, what they want, and how they speak. Anchored to that, the AI voices them and fills the small edges itself.

A long campaign overflows any context window. Keep a searchable record in Foundry so the AI reads from your notes, not from a fading window.

Run combat with an AI that cannot cheat. Foundry's own dice enforce range, damage, and conditions, while you stay the DM.

You know these modules cold and never get to play one. Bring a published adventure, take a single character, and Familiar runs the DM's side around you: the monsters, the NPC voices, the 2024 5e rules.

One PC, one player, a microphone, and an AI playing two heroes and every monster. The exact rig behind my own game, and the order to build it in.

A copy-paste rules pack that makes any AI a more disciplined Game Master. Roll only when it matters, run the adventure you prepared, never decide for the players. Every rule in it was paid for at a real table.