MCP server
MCP server integrations expose remote Model Context Protocol tools to Mobius assistants.
An MCP server integration connects one remote Model Context Protocol (MCP) server to Mobius so assistants can call its tools.
Use MCP when you already operate a tool server and want assistants to use it without turning each tool into a Mobius-managed action. MCP tools are discovered dynamically from the connected server.
Capability map
| Capability | Value |
|---|---|
| Provider ID | mcp |
| Auth kind | api_key |
| Connect flow | Endpoint URL with none, bearer, API key, custom header, or OAuth auth |
| Actions | Dynamic tools |
| Events | No |
| Webhook delivery | No |
| Event samples | No |
| Live status | Yes |
Connect an MCP server
| Surface | Support |
|---|---|
| App | Open Build > MCP servers, add a server, and provide the endpoint, auth mode, and optional action prefix. |
| CLI | The mobius CLI does not connect MCP servers yet. Use the app or API. |
| API | Call POST /v1/integrations/providers/mcp/connect with the server endpoint, auth fields, and optional action_prefix. |
Choose a stable action prefix. Mobius rejects prefixes that collide with
reserved provider namespaces such as slack, github, or table.
The app creates MCP servers as team-managed connections, so an organization
administrator adds, edits, reconnects, or removes them. API callers can request
a person-managed server with controller: { "kind": "self" }. Under
Assistant access, grant the exact server to the assistants that need it and
choose its Mobius result audience. If two servers could provide the same
capability, set the intended connection in account preferences or on the routine
rather than leaving the route ambiguous.
Sign in with OAuth
With OAuth (sign in), Mobius reads the server's OAuth metadata, registers itself as a client, and sends you to the server's sign-in page. Tokens are stored encrypted and refreshed automatically.
Some servers, such as Sherweb's, do not let Mobius register itself. They ask you to create the OAuth client on their side first:
- In the form, choose OAuth (sign in) and check Use an OAuth client I created on the server. The form shows the Mobius redirect URL.
- On the server's side, create the OAuth client and add that redirect URL to it.
- Enter the client ID and client secret, then continue to sign in.
When you edit the server later, leave the secret blank to keep the stored one.
Mobius keeps it only while the client ID and the server's sign-in address stay
the same. A new client ID, or a server URL that leads to a different sign-in
address, needs the secret entered again.
Over the API, send the client as oauth_client_id and oauth_client_secret.
The redirect URL is the oauth_callback_url on the mcp entry of
GET /v1/integrations/providers.
Approve a server
Mobius contacts an MCP server only after an administrator approves its exact endpoint URL. Until then, it does not list the server's tools, test the connection, or let assistants call it.
- A server an administrator adds or edits is approved at once.
- When a provider manages your organization, the provider's administrators approve servers. Your own administrators see Not approved yet on the server and choose Ask for approval, which sends a request to the provider's administrators' Inbox. Approving it there makes the tools appear.
- If the request is denied, the server shows who denied it, when, and the reason they gave, with Ask again.
- Changing a server's URL needs a new approval, because approval belongs to the exact URL.
Actions
MCP does not register static action names at boot. After connecting a server, open it from Build > MCP servers to see the tools it currently offers. MCP servers have their own sidebar entry rather than sitting in the integration catalog, because a server's tools are discovered live. If you are automating that check, call the MCP tools endpoint from the API reference; the CLI does not expose MCP tool discovery yet.
The response returns the tool names assistants can call, plus an ok verdict and
a message when the server is unreachable.
Whether an MCP call waits for a person depends on the assistant's approval setting. Mobius trusts only the server's read-only mark: an MCP tool not marked read-only waits whenever the assistant asks before actions that can't be undone. See guardrails. Dispatch still checks the exact server connection, reviewed tool fingerprint when enforcement is on, assistant grant, and result audience. A denial never falls through to a different server.
Tool annotations still control retry behavior. Mobius retries a failed MCP call only when the server positively marks it read-only and idempotent and does not mark it destructive. A missing read-only hint or an idempotent hint on its own never permits an automatic retry.
Events
MCP server integrations do not register source events.
Next
- Review server access in Connect accounts.
- Give assistants access through tools and skills.
- Use custom code with workers when the tool should run in your process instead.