Choosing an AI model
Which model holds a tool chain together, where to get one, and when to turn the thinking up or down.
Guide
MCP vs API: which to choose.
You bring your own AI, two ways. Drive Familiar from a Claude, ChatGPT, Gemini, Grok, or Muse Code subscription you already pay for, or paste a provider API key into the built-in chat and pay per token. Both routes reach the same tools, so the choice comes down to cost and how you play.
Which should you pick?
The short version: pick MCP if you hold one of those subscriptions and play most weeks, because it already covers the AI and nothing extra is billed per token. Pick an API key if you want a specific model, tighter control over spend, or you hold no subscription to lean on. For nothing per token at all, point the built-in chat at a model running on your own hardware.
The subscription route is not unlimited. It spends your plan's normal message and usage quota, so a marathon night can still hit its rate limits. It adds no per-token bill on top, but the usage is never free.
| Factor | MCP (your subscription) | API key (built-in chat) |
|---|---|---|
| Who bills you | Your chat subscription, no per-token add-on | Your provider, per token |
| Cheaper when | You play most weeks | Light or occasional play |
| AI cost | The flat subscription you already pay | Roughly $0.50 to $3 a session |
| Setup | Add a connector, the wizard writes it | Paste a key and start typing |
| Model choice | What your plan includes | Any model the provider offers |
| Offline | No, the subscription runs online | Yes, pointed at a model you run |
| Players asking Familiar in the table chat | Your client answers when you say "check the table" | Answered automatically |
| Chat-only extras | Not over MCP, though your client can search the Familiar Studio library and re-file its images | Transcription, dictation, NPC auto-pilot (D&D 5e), slash commands, drag-and-drop, the Edit button on an image |
Both paths reach the same tools. What differs is who you pay, and a short list of conveniences the built-in chat runs on its own.
What does each one actually cost?
Start with the part that does not change. Familiar itself is $6 a month, $48 a year, or $99 once for life, the same whichever route you pick. The monthly and yearly plans start with 14 days free. On top of that sits the AI cost, and that is where the two split.
On a subscription, the AI is already paid for. A Claude, ChatGPT, Gemini, or SuperGrok plan is a flat monthly price, and so is a Muse Code subscription. Connecting one over MCP adds no per-token charge on top. Over a run of weekly sessions, that flat price usually buys more play than metered tokens do.
On a provider key, you pay per token, in and out, for every message. A single session runs roughly $0.50 to $3, depending on the model. Rates move, so check current provider pricing before you commit. Light play stays cheap; volume is where it adds up.
Or pay nothing per token at all: point the built-in chat at a model on your own hardware, and no provider bills you. Either way the AI cost is yours directly. Familiar never marks up or proxies your tokens.
One thing trips people up: a subscription and the API are billed apart. A ChatGPT plan does not hand you API credits, and an API balance does not unlock the chat app. You are choosing one route or the other, not topping up a shared pool.
When is MCP the cheaper route?
MCP is the easy call when you already pay for the subscription. You need a plan that exposes MCP connectors; the connect guide lists which ones per assistant.
Claude connects from Anthropic's own apps, ChatGPT through OpenAI's Codex, Gemini through Google's Antigravity and Grok through xAI's Grok Build; Muse Code is Meta's own agent. Whichever you use, you are talking to your usual assistant, only over MCP.
Familiar's tool catalogue spends less of that plan than its size suggests: no client reads every tool description at connect. The capabilities page covers what it does cost.
- You play regularly. A flat monthly price suits a weekly game better than a meter that climbs with every session.
- You want a predictable cost. One subscription, one known number each month, with no per-token surprises after a long night.
- You are happy inside your plan's limits. A typical session fits; a long one can brush the plan's rate cap.
When is an API key the better call?
The API key wins when you want control, or when you have no chat subscription. It is the simplest way to start: pick a provider, paste a key, and talk to your game from Familiar's chat window in Foundry. The conveniences that live in that chat window only are in the comparison table above.
- You want a specific model your subscription does not include. A key reaches the full provider catalogue, not just what a chat plan ships.
- You want fine control over the model and the spend, paying only for the tokens a session uses.
- You have no chat subscription. With light or occasional play, a per-token bill can come in under a monthly plan you would barely use.
- You run a headless or automated setup where a desktop chat app is not in the picture.
- You want to play offline. A model on your own machine answers through this same chat, with no provider in the path and no token bill.
Which model should you run?
One more lever sits on top of the route: the model. A bigger model reasons better over a messy fight but costs more per token, and how hard it thinks costs tokens too. Whichever route you pick, you choose the model and can change it whenever you like. Picking one is its own guide.
Pick the cheaper route and start
Connect over MCP or paste an API key, whichever the table above points you to. Neither is locked in; you can switch routes later without redoing your prep.
Install Familiar in Foundry to get going. If you are weighing the two against your own habits, the Discord is a good place to ask.
More in Choices around the connection
Running a local LLM
Run the model on your own PC, so your world never leaves the machine. One settings tab and one switch. Without a discrete GPU, expect minutes per turn.
New to Familiar? I'm Ryan, the person who built it. The Discord is small and brand new, so if you join now I'll help you get set up myself.