Grok Build drives a Foundry VTT game on the SuperGrok plan you already hold.

Which Grok this is

Grok Build runs in a terminal window, on Windows, Mac or Linux, and signs in with the account behind your SuperGrok subscription. That is the whole entry ticket. The plan you hold for the chat is the plan that drives your game, and the install is one line from xAI for your operating system, printed on the wizard card in Familiar's MCP tab.

The Grok app and grok.com sit this one out, for a mechanical reason rather than a policy. Their connectors accept a server on the public internet and nothing closer, and Familiar runs on the computer beside your Foundry window. Grok Build runs there too, which is why it can see it.

• Install Familiar in FoundryFamiliar first, in the world you GM. The terminal has nothing to talk to until the module is on.
• Grok Build CLI: the setup stepsThe wizard card that carries your world's secret, and the failures that are not Grok's.

One command, then the doctor

With grok signed in, Familiar goes in with the line below, run in a terminal rather than inside Grok. Copy the finished version from the wizard card: it carries this world's real secret, and on Windows the command name and the antivirus setting the connect guide explains. Run it a second time and it replaces the entry instead of adding another.

Then the check the CLI ships with. grok mcp doctor familiar starts the server once and reports what it found, and a line reading handshake OK with a count of tools discovered means the link is real rather than merely written down. Keep the name on the end of that line; the snag list further down says what happens without it.

Rather not type it? The card also carries Copy setup prompt. Once Grok Build is installed and signed in, paste that prompt into grok itself and it registers Familiar for you, asking your approval as it goes.

grok mcp add familiar --env FAMILIAR_WS_SECRET=<your-secret> -- npx -y familiar-vtt

• Three ways through the setupThe card, a help prompt for any AI chat, or the setup prompt above: pick one.
• Getting a published adventure into FoundryThe journals, sheets and outline a terminal agent runs a module from.

If another agent on this computer already runs Familiar

Grok Build reads the MCP servers, skills and hooks of the coding agents it knows how to read, Cursor among them, and it does so by default. Set Familiar up in one of those and it turns up inside Grok with no Grok-side step at all, next to every other server that agent holds.

The command above still wins for familiar. An entry in Grok's own config outranks an imported one of the same name, so running it never leaves you with two. What you may not want is the rest of the import, and the wizard card names the settings that keep the other agents' servers, skills and hooks out of Grok's list. The connect guide names the agents.

• The clients, side by sideWhich agents Grok Build reads by default, and the per-client table.

What a terminal changes at the table

Grok Build takes Familiar's full tool set from the first message. It reaches tools through a search layer of its own, so carrying every bundle costs it nothing up front, and there is no set to widen before a weather tool or a playlist tool will answer. Whatever you ask for happens in the Foundry tab in your browser: the scene switches, the token moves, the rain starts. What comes back to the terminal is a line saying so.

Pictures take a different path. A generated image, or the annotated screenshot of the live battlemap, comes back to Grok as something it reasons over, and whether your terminal draws it as well is the terminal's business; the image itself is already saved in your Foundry world.

The campaign is the one thing Grok Build does not bring. It plays the adventure you imported, page by page, from the journals, sheets and statblocks already in your world, and it fills in between those pages rather than writing new ones.

• Combat & Initiative
• Scenes & Tokens
• Audio & Playlists

• What stays in the Foundry windowWhat only the built-in chat can do, and why a terminal never sees it.
• Everything Familiar can doEvery bundle Grok Build can reach, listed by domain.
• How to play D&D with AIWhat a session looks like with a terminal on the other side of the table.
• Playing something other than D&D 5e?The systems with a page of their own, and what changes on each.

What to type once the doctor says OK

Type grok, start a conversation, and send the product's own line first, the one the wizard card closes on. If Grok answers with your world's name, everything under it is safe to try.

The four after it each lean on something this page has claimed: a combat bundle that was there from the first message, the scene and the weather on it, a sound that plays in Foundry while the terminal gets the receipt, and the clock.

• The verify line

  Use Familiar's get-world-info tool

  Copy The verify line
• Open a fight

  Start combat with every token on the map and roll initiative for the monsters.

  Copy Open a fight
• Change the weather

  Make it night on the current scene and start rain.

  Copy Change the weather
• Start the music

  Play the playlist called <playlist name> in Foundry and tell me once it is running.

  Copy Start the music
• Move the clock

  Advance the in-game clock by eight hours and give the party a long rest.

  Copy Move the clock

Where only Grok Build trips

Every entry here comes from the terminal or from Grok's own habits, and none of them needs a reinstall. The failures every MCP client shares have one home, the connect guide, linked below.

• grok is not recognised, seconds after the installer finished

  The installer adds grok to your PATH, and only windows opened after it can see that. Close the window you installed from, open a new one, and type grok --version there; a version number means the install took. Sign in from that new window too.

• grok mcp doctor familiar reports a startup timeout

  The first start downloads the server, and Grok gives it half a minute by default. Open ~/.grok/config.toml, add startup_timeout_sec = 60 under the [mcp_servers.familiar] heading, and run the doctor again. Or get the download out of the way first: run npx -y familiar-vtt once in a terminal and let it stop on its complaint about the missing secret, which is the expected ending there.

• The doctor started every server on the computer

  The name was missing. grok mcp doctor on its own starts every server Grok can see, the imported ones included and even the ones you switched off, so a machine with other agents on it watches all of them spawn. End the line with familiar, every time.

• grok mcp list shows familiar, but the add command had failed

  The list is not the test. It also shows servers Grok imported from another agent's config, so familiar can sit there with no Grok entry behind it. Run the add command again, then the doctor with the name on the end; the handshake line is the proof.

• You added Familiar as a custom connector on grok.com and it never connects

  It cannot: that route needs a server the public internet can reach, and Familiar runs on your own machine. Grok Build is the way in, and it is the route this page describes.

• You switched a tool bundle on mid-session and Grok cannot find the new tool

  Grok Build does not act on a changed tool list, so a tool that arrives after the session started stays invisible to its search until the next one. Start grok again and ask once more. On this client the case is rare, since the full set is there from the start unless you narrowed it yourself.

• The failures every MCP client sharesEverything that stalls a link on any client, from Safari to a hosted game, answered once.
• Worked the list and still stuck?Paste what grok --version and the doctor printed; that is enough to start from.