Connect Claude Code

Claude Code can talk to Creator directly: one command adds the running editor as an MCP server, and from then on you can ask about the open map and propose changes to it from your terminal. This page is the whole setup.

You bring your own Claude account. Creator holds no key of its own, makes no call to any service, and sends no telemetry.

What you are connecting to

While Creator is open it can run a small server of its own, and three facts about it are worth knowing before you start:

• It listens on 127.0.0.1 only. That address is your own machine and nothing else. No port is opened to your network or to the internet.
• It exists only while Creator is open. Close Creator, or press the stop button, and the server is gone.
• Nothing about your map leaves the PC except what you yourself send into your own Claude session.

Every change waits for you. Claude can read the open map freely, but a tool that would change something never acts on its own: it returns a proposal, Creator shows a confirm card, and nothing moves until you click it. There is no setting that turns that off.

Claude Code is the one client that speaks to Creator’s server directly, so it needs no extra program installed. (Claude Desktop cannot, which is why it has a page of its own.)

Step 1: start Creator’s server

1. Open Creator.
2. Open Preferences and choose the CONNECT tab. On the start screen, PREFERENCES is the button beside HELP at the bottom left; with a map open, it is EDIT > Preferences…. You do not need a map open to connect.
3. Click START.

The tab now shows the port it is listening on (8790 unless you changed it) and this session’s token, which is the password Claude Code uses to talk to it.

To start it automatically instead, launch Creator with the -mcp flag:

RustCreator.exe -mcp

That starts a fresh token each time. To keep one token across restarts, use the Launch line the CONNECT tab shows instead; the token section below explains it.

Step 2: add Creator to Claude Code

The CONNECT tab shows the exact commands, with the live port and token already in them, and a COPY button that puts both on your clipboard. They look like this:

claude mcp remove creator --scope user
claude mcp add --transport http --scope user creator http://127.0.0.1:8790/mcp --header "Authorization: Bearer <token>"

Run both in a terminal, in that order, with <token> replaced by the token from Preferences > CONNECT (the COPY button does that for you). The first line removes an entry an earlier Creator session left behind, because claude mcp add refuses a name it already has; on a first setup it only says there was nothing to remove.

Then type /mcp in Claude Code to connect.

A Claude Code session that is already running does not notice a new or changed entry until you do.

Where the entry is saved is set by --scope, and both lines use --scope user, so the remove always finds the entry the add made:

Scope	What it means
--scope local	The default. Only this project, only you.
--scope user	All of your projects, still only you. Usually what you want for Creator.
--scope project	Written to .mcp.json in the project and shared with anyone who has the repository.

Creator’s token changes every time its server restarts, so do not use --scope project for it: that writes a credential into a file other people can read, and it will be stale by tomorrow anyway.

Step 3: check that it worked

1. Run /mcp inside Claude Code. It lists each server with its health, and creator should read connected.

2. With a map open in Creator, ask:

   What map is open in Creator right now?

Claude calls the get_map_summary tool and answers with the map’s size, its seed, how many prefabs it holds, and which content snapshot it is being rendered against. That answer means the connection works end to end.

Useful commands while you set this up:

claude mcp list            # every server you have added, and its health
claude mcp get creator     # what was stored for this one
claude mcp remove creator --scope user  # remove it again

What “confirm in Creator” looks like

Ask for something that changes the map and Claude does not change it. Instead:

1. Claude’s answer says it has proposed the change.
2. Creator shows a confirm card describing exactly what would happen, and naming the client that asked for it (the name that client gives itself, such as claude-code), so with two clients connected you can tell whose request it is.
3. You click to accept or dismiss it. Dismissing it is a real refusal, and Claude is told so.
4. Long work, such as generating a world, then runs as a job. Claude reads its progress with get_job rather than waiting on the call, so nothing times out.

So keep Creator’s window where you can see it: a proposal that nobody clicks is a request left hanging.

Is the card up? Taking a request back

Claude can see enough of your screen to know whether you can answer it, and no more:

• Which screen you are on. get_map_summary says whether Creator is on its start screen, loading, showing the generation screen, in the editor with a map open, or in the prefab workspace, and whether a map is fully open. After FILE > Unload Map it says that no map is open.
• Whether its request is waiting for you. The same answer, and get_job, say whether a request is still waiting for your click, how many seconds are left before it expires (a card nobody answers expires after ten minutes), and whether its confirm card is actually on screen.

It sees nothing else: not the names of Creator’s windows or panels, and nothing about how Creator is built.

Taking a request back. If Claude changes its mind while a card is up, it can withdraw its own request with the cancel tool. The card closes, Creator tells you the request was taken back, and nothing changes. Cancel needs no click, because all it can do is take a request back. It never stops work you have already approved: a generation you clicked GENERATE on runs to the end, because stopping it part way would leave a half-built world.

Standard Mode and Creator Mode from Claude

The recipe Claude builds with you is in one of the two modes the Procedural Generation panel has.

• Standard Mode is Rust’s own generation for a size and a seed, with the game’s own percentages and filters. A new recipe starts here.
• Creator Mode is everything beyond that: generating on a heightmap of your own, leaving monuments out, pinning a monument to an island, and bridges with one road around a group of islands. Ask for any of those and the recipe switches to Creator Mode on its own, and the tool’s answer tells Claude it did, so Claude can tell you.

Claude can see which mode the open map and the draft are in, and it can set the mode directly if you ask.

Choosing monuments. Claude can list every monument your Rust content carries, one row per monument with its family, and leave any of them out of the recipe, or a whole family. It means exactly what unchecking the monument in the panel means: a monument left out is never placed, and the ones left in are still placed by Rust’s own rules.

A heightmap from a file. Claude can point the recipe at a .raw heightmap, but only one inside Creator’s own folders: the Creator maps folder in Documents, the folder of the map that is open, the recipe library, or Creator’s data folder. A path anywhere else is refused, and the refusal names the folders. To use a file from somewhere else, move it into one of them, or import it yourself in the panel’s LAND section.

The confirm card. A Creator Mode generation’s card carries the CREATOR MODE badge and opens with the same sentence the panel’s own confirm does, “Creator Mode: this map will not be a vanilla generation.”, followed by the land, how many monuments are left out, how many are pinned, and whether bridges are on. A Standard Mode card is unchanged.

Naming monuments

Claude can use a monument’s own name, as the list shows it (for example Launch Site), in any of the five monument fields of a recipe, and Creator turns the name into that monument’s exact key the moment Claude sets the field. A name that matches no monument is refused on the spot, with the closest names, so a misspelt monument is caught before anything is generated. What each list matches:

Field	What an entry can be	What it does
monuments.exclude	a monument’s name, file name or key, or a whole family as family:<Family Name>	Leaves those monuments out and nothing else (Creator Mode).
monuments.blacklist	a monument’s name, or any part of a prefab’s key	Leaves out every prefab whose key contains it, monument or not.
monuments.whitelist	a monument’s name, or any part of a prefab’s key	Places ONLY prefabs whose key contains an entry, so it also removes rocks, trees and road furniture.
monuments.set	a monument’s name, file name or key	Only these monuments: no other monument is placed, and everything that is not a monument generates normally.
monuments.names	monument=Map Name, the monument as a name, file name or key	Gives that monument your own Map Name on the in-game map. Every copy of that monument the map places gets the name, in either mode.

monuments.set limits monuments only. A map limited to four monuments by the set has only those four monuments, and still has its rocks, jungle trees, road furniture and tunnels. The whitelist is the one that filters every prefab. To keep a few monuments out instead, ask Claude for the exclude list or the blacklist.

A recipe that would place no monument is refused before the card. If the monument lists leave nothing Rust can place on a map of the recipe’s size (every monument in the set is too big for the map, the set or the whitelist names no monument, or the exclude list and the blacklist leave them all out), generate and replay refuse it with MONUMENTS_SET_EMPTY, say which list did it and how to fix it, and show no confirm card. With no map open, get_validation checks the recipe Claude is editing and reports the same finding.

The token changes every time the server starts

Creator mints a fresh token each time its server starts, and stopping the server makes the old one useless immediately. That is deliberate: a token that has been stopped can never be revived.

After you restart Creator, run the two lines from Step 2 again with the new token (the CONNECT tab’s COPY gives you both, remove first), then type /mcp in your Claude Code session. A session that is already running does not notice a server that was removed and added again, or a Creator that restarted, until you do.

If you would rather not do that every session, launch Creator with the Launch line the CONNECT tab shows:

RustCreator.exe -mcp -mcptoken=<token>

The tab fills in this session’s token, so relaunching with that line brings the server back with the same token every time and the entry you added keeps working across restarts: after Creator restarts you only type /mcp in Claude Code to reconnect. You can also put in a long string of your own in place of <token>. Treat it like a password: anything on your PC that knows it can drive your editor. If you chose a different port in the CONNECT tab, the tab’s line adds -mcpport= for it.

The recipe Claude is building with you lives in Creator and is gone when Creator closes. Ask Claude to export it first (export_recipe), or save it to your recipe library, if you want to keep it.

The stop button

Preferences > CONNECT > STOP is the kill switch. It closes the server and voids the token in the same moment, so every client holding it is refused from then on. Use it whenever you want the door shut, and remember that closing Creator does the same thing.

The CONNECT tab also lists the last 50 tool calls, with the time, the client, the tool and the size of what moved. It deliberately does not record the contents of anything, so your map’s data never appears in a log.

Troubleshooting

/mcp shows creator as needing authentication. Claude Code says that when the server answers 401, which here means the token is wrong. Creator has restarted since you added it, so the token it was given no longer exists. Run the two lines from Step 2 again with the current token (remove first), then type /mcp.

/mcp shows creator as failed to connect. Nothing is listening on that port. Creator is closed, its server was never started, or it is on a different port. Open Preferences > CONNECT and check that it says it is listening, on the port your claude mcp add line named.

Calls fail with 403. Creator refuses any request that does not look local, which is what stops a web page in your browser from driving your editor. Check that the URL in the add line is exactly http://127.0.0.1:<port>/mcp and that no proxy is rewriting it.

Creator will not start its server: “port in use”. Something else on your PC already holds port 8790. Type a different port into the Port field in Preferences > CONNECT, click START, and add the server again with the new port in the URL.

A tool’s answer is cut short. Claude Code truncates a large tool result (about 25,000 tokens by default, MAX_MCP_OUTPUT_TOKENS). Creator’s catalogs page rather than dump, so ask for the next page, or narrow the question.

Creator says a tool cannot run right now. Some tools need a map open, and none of them will start while a generation is still running. The tool’s own answer says which of those it is.

You can generate as many times as you like in one session. Generating while a map is already open replaces it, so that confirm card says in as many words that an unsaved world is destroyed: save first if you want to keep what is on screen.

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Claude Code’s own steps (the add command, the scopes, /mcp, and what it does with a 401 or 403) were checked against Anthropic’s documentation on 2026-09-15: Connect Claude Code to tools via MCP.