Connecting Your Own MCP Servers
Add an outside MCP server so Muin's agents, workflows and Ask Muin can use its tools, choose who may use them, and read every call it made.
An MCP server is an outside service that offers tools over the Model Context Protocol, for example a search over your own knowledge base or a system your team already runs. Connecting one lets Muin use those tools alongside its own.
This page is about servers you connect to Muin. To let Claude or another assistant sign in to Muin, see Connecting Claude to Muin.
When you’d use this
- Your team keeps facts in a system Muin does not connect to, and you want agents to read them.
- You want a custom agent or a workflow step to call a tool your own server provides.
- You want Ask Muin to answer from that server’s facts as well as your Muin records.
Finding it
Sidebar → Settings → Integrations → MCP Connections. The page has two tabs: the assistants that sign in to Muin, and the servers Muin connects out to. Open the outbound tab to see your servers.
Adding a server
- Click Add MCP Server.
- Give it a Name and the Server URL.
- Pick how the server wants Muin to sign in: no sign-in, a bearer token, or an API key sent in a header. Paste the token or key under Credentials. It is stored encrypted and never shown again.
- Save. Muin connects and lists the tools the server offers.
Open the server to Test Connection, Refresh Tools when the server adds new ones, or delete it.
Who may use its tools
A server’s tools are off for everyone until you choose a permission for them. On the server’s page, under Who may use this server’s facts in chat, pick the feature a person must hold:
- Reading through one of its tools needs view on that feature.
- Changing anything through one of its tools needs edit on that feature.
Leave it unset and nobody, including agents, can use the server.
Draft grounding visibility decides whether facts from this server may appear in replies sent to people outside your organization. It starts as Internal (never in drafts). Choose Public (may ground drafts) only for data that is safe to share with senders.
Where its tools show up
Once permitted, the server’s tools appear wherever Muin offers tools:
- Custom agents. Pick them in the agent’s tool list, like any built-in tool.
- Workflows. Use them in a tool step.
- Ask Muin. It can call them when your question needs them.
Each person and agent sees only the tools they are allowed to use.
What waits for approval
Muin treats every tool from an outside server as a change, even one the server describes as read-only, because Muin cannot check what the server does. A change never runs on its own: it appears as a preview in Inbox, and runs once a person approves it. See Approving Agent Changes.
Muin cannot reverse a change made on an outside server. Undo says so and names the server, and only that server can reverse it.
Reading what it did
The outbound tab shows, for each server, how many calls were made and how they ended. Open the calls to see when each one ran, which tool it used, and whether it was Answered or failed. Muin keeps a count and a fingerprint of what each call sent, not its contents.
When it goes wrong
| What you see | Why | What to do |
|---|---|---|
| “Connection test failed” | Muin could not reach the server, or the server refused the sign-in | Check the URL and the credentials, then test again |
| “No tools discovered yet.” | The server has not reported any tools | Click Refresh Tools. If it stays empty, check the server itself |
| A tool is missing from an agent’s list | You do not hold the permission chosen for this server | Ask an admin to grant view (or edit) on that feature |
| A change sits in Inbox | Every change from an outside server waits for a person | Approve or reject it in Inbox |
Related
- Connecting Claude to Muin, for assistants that sign in to Muin.
- Building a Custom Agent, to give an agent these tools.
- Approving Agent Changes.