How to play D&D with AI.

Why prep beats improvisation

Ask an AI to invent a campaign and it drifts. It forgets what it said two scenes ago, contradicts the map, and reaches for whatever sounds dramatic next. Ask the same AI to read the prepared page and run what is on it, and the drift goes away. The structure does the remembering, so the model only has to read and execute.

This is why Familiar does not ask the AI to be a novelist. You bring a published adventure with its maps, NPCs, monsters, and journals, so the model has a fixed text to run from. Professional designers already did the hard part: making the plot hold together.

Prep is one lever. The other is the model: a capable one with reasoning headroom holds a messy combat or a tangled scene where a small one slips. The "Choosing an AI model" guide covers that second lever.

• Invent: the model guesses the plot, loses the thread, and rewrites your world to fit its last sentence.
• Read: the model works from the prepared journal page, so the plot, the NPCs, and the stakes stay fixed.
• The difference is not a better prompt. It is whether the material exists before the session starts.

Familiar runs the adventure you bring, it does not author the plot. Give it a prepared character and it voices them, filling the small edges itself.

Prep, read, run

The whole method is three steps. You do the prep once, the AI reads from it every session, and it runs the mechanical side at the table while you stay in the story.

1. 1

   Prep

   Structure a published adventure into Foundry: journals for the story beats, character sheets and statblocks for the cast, and a short session runbook for what happens next.

2. 2

   Read

   The AI reads the prepared pages, so it works from what is written, not what it imagines. Semantic search and a persistent memory keep the campaign consistent across sessions.

3. 3

   Run

   It handles combat bookkeeping and the downtime in between. You scope which capabilities are active, so the AI only touches what you let it touch.

• Journals & Notes
• Combat & AI
• Knowledge & Memory

How this runs at my table

Here is one concrete loop. I prep a published adventure into Foundry: the opening town as a journal, the first dungeon as linked pages, the early monsters pulled from a compendium. My wife rolls up a character. When we sit down to play, Familiar runs the session from that prepared material.

She talks to the innkeeper, and the AI answers in the innkeeper's voice, leaning on the journal and inventing the small stuff on the spot: his mood, a throwaway rumour. Combat starts, and Familiar rolls initiative, tracks turns, applies conditions, and plays the monster turns. When we stop for the night, it summarises the session into a journal entry we both pick up from next week. I get to play a character at my own table instead of running every NPC and looking up every rule.

Start playing

Install Familiar in Foundry, bring a published adventure, and connect the AI you already use. Questions about prep, BYOK, or your first session are welcome in the Discord.