MCP servers

Use Model Context Protocol servers as a capability source. Bring your own tools, or pull from the open ecosystem.

The Model Context Protocol (MCP) is an open standard for exposing tools to AI agents. An MCP server publishes a catalog of tools at an endpoint; clients (like Guilde's operators) can call those tools.

If HTTP integrations are individually curated by Guilde, MCP servers are the open ecosystem — you, your vendor, or the community can publish tools without going through Guilde.

In the Actions list, MCP-provided actions appear under their server's name (e.g. the github row with 90+ sub-tools); the operator calls them the same way it calls a built-in action.

When to use MCP

The capability you want isn't covered by a Guilde connector yet
You're publishing internal tools (a custom database query catalog, a proprietary inference service) for your team's operators
You want community-built capability — filesystem access, browser automation, Postgres clients, design tools, scientific computing
A vendor publishes their integration as an MCP server (more do every week)

How MCP servers plug in

Settings → Providers → MCP → Add MCP server
                                  │
                                  ├─ Hosted ─ Guilde mounts it for you
                                  ├─ External ─ You provide a URL + auth
                                  └─ Sandbox ─ Run an MCP server in a
                                              sandboxed container

After adding, the server's tools appear in the operator's available capability set (subject to skill / role gating). The operator decides when to call them, just like any other tool.

Hosted vs external vs sandbox

Mode	What it is	Best for
Hosted	Guilde runs the server in our infra. You install from a catalog.	Common open-source MCP servers (filesystem, search, time)
External	You point Guilde at a URL you operate.	Your team's own tools, vendor-published servers
Sandbox	A short-lived container running an MCP server you specify.	One-off jobs, untrusted code, isolated test runs

Discovery

The Smithery catalog (the largest MCP marketplace) is browsable directly from Settings → MCP → Browse. Filter by category (knowledge, productivity, dev), install in one click. Smithery's curation is decent but not exhaustive — vetted enterprise tools tend to come direct from vendors as external MCP URLs instead.

Authentication

MCP servers can require auth — bearer tokens, OAuth, API keys. Guilde's MCP UI handles this:

For OAuth-enabled MCP servers, click Connect and the OAuth dance runs the same way as a connector.
For token-protected servers, paste the token at install. Stored encrypted in your secrets vault.

Tool calls in conversations

When an operator calls an MCP tool inside a conversation, you see:

The tool name (hubspot.contacts.search, fs.read)
The arguments passed
The result returned (truncated if huge, expandable on click)

This is the same UI as connector tool calls — operators don't distinguish the two at the call site, so the user experience is uniform.

What's next

Integrations — the installer that brings MCP servers into your guild
Actions — where installed MCP tools appear
Skills — bundle MCP tools + actions into installable units