Guide
Run D&D 5e with your own AI key (and keep the DM seat)
You already have ChatGPT, Claude or Gemini open in a tab. What is missing is the campaign around it: the map, the tracker, the sheets, and a step where you approve or discard what the model suggests so it never takes over the table.
The key and billing facts here come from the API key tutorial, billing, and pricing as of 2026-09-18. Provider prices change often, so this page describes their shape rather than quoting numbers.
You already have a model. The missing piece is the table
A lot of DMs run their prep like this already:
- Brainstorm in ChatGPT or Claude.
- Paste the NPC into a Google Doc.
- Upload a map to a VTT.
- Track hit points somewhere else again.
- Hope the tab with the model in it does not invent a spell slot in front of the players.
Bring-your-own-key means the same models, inside the campaign, with a review banner between the suggestion and the table. It is not a second subscription to an “AI GM,” and it is not required. If you want no AI at all, do not add a key; the table runs exactly the same. The no-AI route through the app is getting started.
What “bring your own key” means here
As described on the key tutorial (2026-09-18):
- AI features run on an API key from your own provider account.
- It is available on every QuestMaster plan, including Apprentice at $0.
- There is no markup. Your provider bills you for what you use.
- You only need a key for the features you actually want.
- Keys are encrypted at rest, never shown again once saved, and used only for your account.
- You can replace or remove a key any time from Account ▸ API keys inside the app.
And as billing puts it: the paid plans sell more campaigns, more players, homebrew, shops, continent generation and co-DMs. They do not sell AI. AI is not the upgrade.
Which key for which job
This is the same split the tutorial uses. If this table and /help/api-keys ever disagree, trust the help page.
| Job | Provider |
|---|---|
| Text: NPCs, items, factions, modules, recaps, DM chat, tactics | Claude (recommended), Gemini, or OpenAI |
| Images: battle maps, portraits, scene art | OpenAI, or Google’s Imagen |
You do not need all three. One text key is enough to start.
What to generate in prep, and what to generate at the table
Before the session:
- NPC drafts with a portrait, which you approve or discard.
- An encounter you are actually going to run, with the numbers edited to taste.
- A battle map you will put a grid on and calibrate yourself.
- A recap of last week, with anything the party should not know cut out.
During the session:
- A name, a rumour, a shop inventory, a quick “what does this cultist actually want.”
- Tactics suggestions. You still choose the monster’s action.
- Rules lookups through /lookup, which searches the SRD itself. A model is not a substitute for the actual rules text.
The pattern is always the same: the model proposes, you decide what goes on the map. If you would not have time to review it, it is not something to generate in front of players.
What the AI must never do
If anyone at your table is uneasy about AI, it helps to write this down at session zero:
- The AI is not the DM. A human makes every ruling.
- The AI never hides its output from the DM.
- The AI never spends a player’s resources without you.
- The AI never speaks for a player character unless that player asked it to.
- If the key is missing, the session carries on. That is deliberate.
For contrast, Friends & Fables at fables.gg (as of 2026-09-18) is built so that Franz, its AI Game Master, runs the campaign. That is a perfectly valid product for a different job. If that is what you typed “AI dungeon master” into a search box hoping for, this guide is not the match; AI dungeon master tools lays out that category properly.
Foundry’s AI Content Policy (revised 18 March 2026) is about what modules may ship. That is not the same thing as pasting your own key into a built-in assistant.
What it costs, roughly
Any blog’s “Claude costs $X per NPC” figure goes stale quickly, because the providers change their pricing. What does hold, per the help pages as of 2026-09-18:
- Anthropic: pay-as-you-go credits. A few dollars covers a great deal of generation, and Anthropic bills you.
- OpenAI: pay-as-you-go. Image generation is a few cents per image depending on size and quality, and OpenAI bills you.
- Gemini: Google AI Studio has a usable free tier with rate limits. Higher limits need billing on the linked Cloud project, and Google bills you.
QuestMaster adds nothing on top. Apprentice stays $0 whether or not you add a key (pricing). If a generation fails, troubleshooting walks through the usual causes, the most common being a provider account with no credits on it.
Setting it up
The step-by-step walkthrough lives in one place:
sk-ant-, sk-, AIza), and where to paste the key in QuestMaster.The order that tends to work best:
- Start free with Google or a magic link.
- Open the sample campaign (getting started).
- Run a scene without a key, so you know the table itself works for you.
- Add a key only once you want a draft of something.
- Generate one NPC and approve or discard it. That is the whole loop.