Set up the Kater MCP

Select the AI providers your organisation allows, copy the Kater MCP's addresses, and add Kater for everyone in Claude, ChatGPT, Claude Code and Codex.

Audience

Platform admins

Prerequisites

The settings permission in Kater (settings:manage)
An Owner in your Claude organisation, to add Kater to Claude
An admin or an owner of your ChatGPT workspace, to add Kater to ChatGPT

People connect their AI app to Kater through the Kater MCP. On the MCP page you select which AI providers your organisation allows, copy the Kater MCP’s addresses, and follow the steps to add Kater for everyone in each provider’s own admin settings. Kater never adds itself to Claude or ChatGPT.

Open the MCP page

In the Admin console, select MCP under Manage. The page needs settings:manage. Its address is /admin/mcp.

The page has three parts: AI providers, Addresses and Add Kater for everyone.

AI providers

People see and connect only the apps you allow. Kater refuses calls from an app you do not allow.

Row	The apps it covers
Anthropic	Claude, Claude Code, Claude Code in VS Code and claude.ai
OpenAI	ChatGPT and Codex
Cursor	Cursor, which uses the model each person selects in Cursor

Allow a provider. Turn its switch on or off. The change saves at once. Cursor has a switch of its own, because it works with the models of any provider.
At least one provider. You cannot turn off the last provider that you allow. Allow another one first.
Default AI provider. Select one of the providers that you allow. A person uses this provider until they select their own in Profile › AI app, and Ask shows its apps first. When you turn off the default provider, the other provider becomes the default.

When Kater cannot save a change, the switch goes back and the page shows Kater could not save your AI providers. with the reason.

When an app is not allowed

Kater refuses each tool call from an app that your organisation does not allow. The app can still sign in, but its calls fail with words that the agent passes on, such as:

Your organisation does not allow Codex with Kater. Ask an admin to allow OpenAI on the MCP page.

In Profile › Agents, the person sees the same reason on that app’s row, such as “Your organisation does not allow Codex.” Turn the provider on again, and the next call runs.

What the refusal stops

Claude and Claude Code sign in with an identity that Anthropic publishes, so Kater knows them for certain and stops them. Kater knows every other app by the name that the app gives itself when it connects. For those apps, the refusal tells people what to do, but it does not stop an app that gives a different name. Use each provider’s own admin settings to control which apps people can use.

Addresses

Address	What it is for
Kater MCP	The address every AI app connects to. Each person signs in to Kater, and Kater acts as that person.
Read only	For an app that must not change anything, such as a Slack bot. It lists only the tools that read.

Select the copy button beside an address to copy it.

Add Kater for everyone

Do this one time in each provider’s own admin settings. Then each person connects with their own Kater account. The page shows a tab for each provider that you allow, with numbered steps. Each step that needs the address has a button that copies it first, or a box with a copy button.

Add Kater to Claude.

In Claude, open Organization settings, Connectors. Select Add, then Custom, then Web. Name it Kater, paste the address and select Continue two times. Select Sign in now and Use Claude’s published identity, then select Add. Only an Owner can add a connector. Open Claude’s connectors copies the address first.
Allow the tools that only read.

In Organization settings, Connectors, open Kater. Under Tool permission restrictions, set the read-only tools to Always allow. Leave the write/delete tools on Needs approval, so a person approves each change before Claude makes it.
Give Claude Kater’s rules.

In Organization settings, Organization and access, add Kater’s lines under Organization instructions and select Save changes. Claude then asks Kater first, shows Kater’s chart, and does not work out a figure that Kater does not have. Kater cannot see whether the lines are there. The page has a copy button for the lines:
```
Kater is our source for company data. For any question about our numbers, ask Kater first.
When Kater shows a chart, do not draw the chart again, and quote its figures as Kater writes them.
Do not work out a new figure from Kater's figures. When Kater does not have a figure, say so, and offer to ask the data team to add it.
```
Tell your team.

Each person opens Customize, Connectors in Claude, selects Connect on Kater and signs in to Kater. Kater shows the same steps in Profile › AI app, and Ask sends them there until they connect. See Connect your agent.
Claude Code.

Claude Code gets the Kater connector when a person signs in with their Claude account. It names the tools after the connector, such as mcp__claude_ai_Kater__<tool>, so keep the name Kater. In Organization settings, Claude Code, Managed settings, add the settings that the page gives, to allow the tools that only read. They also cover a Kater that a person adds with claude mcp add, whose tools are mcp__kater__<tool>. The settings list both names for each tool that only reads:
```
{
  "permissions": {
    "allow": ["mcp__claude_ai_Kater__<tool>", "mcp__kater__<tool>"]
  }
}
```

Add Kater to ChatGPT.

In ChatGPT, open Plugins, select + and then Add custom MCP server. Name it Kater, paste the address and set up OAuth sign-in. Accept the warning and select Create as a plugin. Open ChatGPT’s plugins copies the address first. ChatGPT allows custom MCP servers on its Business, Enterprise and Edu plans, on the web. You do not need to turn on Developer mode first.
Publish it to your workspace.

In the admin console, open Plugins and select Manage Legacy Apps. Open Drafts, then publish Kater. Only an admin or an owner can publish.
Allow read actions.

In Workspace settings, General, under Plugin permissions, select Allow read actions. ChatGPT still asks before each change.
Turn on new tools.

ChatGPT keeps the tools that Kater had when you published it. When Kater adds a tool, open Kater’s Action control in Workspace settings, Apps. Select Refresh and turn the new tool on. To skip this for tools that only read, set New actions to Only enable new read actions.
Codex.

Each person adds these lines to ~/.codex/config.toml, with your address, then runs codex mcp login kater. The Codex CLI, its IDE extension and Codex in the ChatGPT desktop app read this file. Codex asks before a tool that changes something, and runs the tools that only read.
~/.codex/config.toml
```
[mcp_servers.kater]
url = "<address>"
default_tools_approval_mode = "writes"
```

When you allow only one provider, the page shows its steps with no tabs. The tab you open is in the page’s address, such as /admin/mcp?setup=openai.

Cursor needs no admin step. Each person adds Kater with Add to Cursor in Profile › AI app. See Connect your agent.

If something looks wrong

A person sees “Your organisation does not allow …”. Their app belongs to a provider that you do not allow. Turn the provider on under AI providers, or ask them to select an allowed app in Profile › AI app.
The switch of a provider is off and you cannot change it. It is the last provider that you allow. Allow another one first.
Default AI provider cannot change. You allow only one provider.
Kater is not in a person’s Claude connectors. Check that an Owner added it in Organization settings, Connectors.
Kater is not in a person’s ChatGPT plugins. Check that you published Kater from Drafts in the admin console.
A new Kater tool does not show in ChatGPT. Select Refresh on Kater’s Action control and turn the tool on.