Custom API and MCP server
A service that is not in the catalog can be connected by you: on the Custom API tab by its API address and key, or on the MCP servers tab if the service offers an MCP server. Both tabs are under Integrations for everyone. The general rules of connections (statuses, Read-only, disconnecting) are in Connecting services, and how the agent decides which change to make on its own and which to send for confirmation is in Action approval.
Custom API
Any service with an HTTP API: your accounting system, a CRM on your own server, a service with no ready integration.
What the agent can do
Calls the endpoints of your API: reads data with GET requests and changes it with the other requests. Which endpoints exist and what they are for, the agent learns from the Hint for the agent field, so the more precise the hint, the fewer unneeded requests.
Before you start
- The API address from the service's docs, usually starting with https://api.
- A key or token from the service's account. If the service needs no key, you do not need one.
- If the server is reachable only inside the office network, the desktop app on a computer in that network (Apps).
Steps
Open the Custom API tab
Under Integrations open the Custom API tab and click Add API.
Enter a name and the address
Name: what you and the agent will call the connection. API address: the address from the service's docs. If the address is internal, a hint under the field says that requests go through your computer.
Paste the key
Paste the key or token from the service's account into API Key. If the key must be sent in a particular way, click Configure how the key is sent: there you choose where the key goes (a header or a Query parameter), the header or parameter name and the Auth scheme. If a key is already saved for this address, leave the field empty and that key is used.
Describe the endpoints for the agent
In Hint for the agent list the endpoints one per line with a note, for example GET /customers?email= (search customers) or POST /orders (create an order).
Connect
Click Connect: the address and key are checked with a request to the service. If the service says the key was not accepted or is needed, the form tells you. When you are sure everything is right, you can click Connect without check.
The key is stored in Connection keys on the Variables tab and is added to every request to this API.
Permissions to grant
The agent works with the rights of the key you pasted. For reports, issue a read-only key in the service: then data cannot be changed even if you ask.
Limitations
- A POST counts as a change. Requests other than GET are made as changes, and the address and method of your API do not say what exactly changes. If a change came as a confirmation card, the permission is not remembered for later calls.
- A POST that only reads (a search, a filtered report) goes into POST endpoints that only read: one path under the API address per line, starting with /, without spaces. The agent calls those endpoints without asking, and a read-only helper may call them. Only you set this list in the form, the agent cannot change it.
- Slow replies. If the service answers slowly, set Response wait, seconds. Empty uses the default.
How to revoke access
Open the connection on the Custom API tab and click Disconnect. The key itself stays valid in the service: to close access fully, delete or reissue it in the service's account.
Troubleshooting
- The service didn't accept the key: check the key or set how it is sent under Configure how the key is sent.
- The service says it needs a key: paste the key from the service's account.
- The agent calls the wrong endpoints: extend the Hint for the agent, name the endpoint and what it returns.
- An internal address does not answer: open the desktop app on a computer in the same network.
Find the customer with the email ivanov@example.com in @my_api and show their latest orders. Don't change anything.
MCP server
A server speaking the MCP protocol that gives the agent ready tools: many services publish such an address, and you can also run one yourself.
What the agent can do
Calls the tools the server declares. When you add a server it is checked, and the window shows Tools detected: that is how many tools the agent gets.
Before you start
- The server address: the service gives it, look for "MCP" in its settings or docs. Or a JSON config from Claude, Cursor, VS Code or Zed.
- Sign-in details if the server asks for them: a token, a key or an account on the service.
- For a server on your computer: an address like http://localhost:port and the desktop app open (Apps).
Steps
Open the MCP servers tab
Under Integrations open the MCP servers tab and click Add MCP server.
Paste the address or config
Paste an address like https://example.com/mcp or a JSON config into Server URL or config. A config can be uploaded with Upload .json: one config connects several servers at once.
Choose the sign-in
The server is checked, and the Sign-in line shows what it requires: not required, Bearer token, API key header, Basic authentication or with your account on the service. For a token or key fill in Authentication token, for the account sign-in click Authorize and allow access on the service's page. Your own headers go into HTTP headers.
Check the tools
Make sure the window shows Tools detected, and connect the server.
Permissions to grant
The agent gets exactly the tools the server declares, with the rights of the token or account you signed in with. If the service can issue a read-only token, use it for reports.
Limitations
- Only servers with an address. A server that runs as a command on a computer and has no address cannot be connected. An http(s):// address works, including http://localhost:port on the computer with the desktop app.
- A local server lives with the desktop app. While the app on that computer is closed, the agent cannot reach the server.
- Group chats. In a group chat with other people and in a messenger group, MCP server tools are not available to the agent, see Group chats.
How to revoke access
Open the server on the MCP servers tab and click Disconnect. A token or permission granted in the service itself is revoked there.
Troubleshooting
- There's no MCP server at this URL: check the address, it usually ends with /mcp.
- The server isn't responding: check the URL and try again.
- The cloud can't connect to this address: the server is reachable only on your network, use an address like http://localhost:port or an IP on that network and open the desktop app.
- This server runs on your computer: open the desktop app on it and try again.
- This is a local server: the config has a server with no address, run it with an http(s):// address.
- Couldn't read this config: check the JSON format.
The service you need is not there
If the service has neither an API nor an MCP server, ask the team for an integration right from the chat: how to do it is on the Connecting services page.
Frequently asked questions
The service I need is not in the catalog. How do I connect it?
If the service has an API, connect it on the Custom API tab under Integrations: enter a name, the API address and a key. If the service offers an MCP server, connect it on the MCP servers tab. To ask for a ready integration, write in chat and the agent prepares a Report to the team card.
The agent asks for permission on a POST request that changes nothing. How do I stop that?
Every POST of a custom API counts as a change. If an endpoint only reads, add it to POST endpoints that only read in the connection settings: one path per line, starting with /. The agent calls those endpoints without asking.
My MCP server runs on my computer. Can I connect it?
Yes, if it has an address like http://localhost:port or an address on your network. Requests go through the desktop app on that computer, so it has to be open. A server that only runs as a command, with no address, cannot be connected.
Can I paste an MCP config from Claude or Cursor?
Yes. The Server URL or config field takes a JSON config from Claude, Cursor, VS Code or Zed, and you can also upload it with Upload .json. Servers in the config that have an address are connected, local servers without one are skipped.
See also
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