Adding an MCP integration step to a flow

Flows aren't limited to AI work — a step can call a connected external service. These are MCP integration steps, and they let a flow read from or write to the tools you've connected through Composio.

What an MCP step is

Besides role sub-agent steps, a flow step can be an MCP tool call. This kind of step runs a connected Composio tool, identified by its tool slug, as part of the flow's sequence. That's how a flow can, say, pull data from a service or post a result to one.

Adding one in the node editor

In the visual node editor, a connected-MCP-tool node compiles into an MCP integration step when you build the flow. Wire it into the graph like any other node — its edges become dependencies, so it can consume the output of earlier steps or feed later ones.

Connecting the integration first

MCP steps only work with integrations you've actually connected. Integrations are powered by Composio and connected per-user from the Connections section, where you authorize each one through its real OAuth or credential flow. The Composio key is resolved server-side and never reaches the browser.

Approvals for write actions

Integration actions are classified as read or write. Read actions run immediately. Write actions — posting, sending, creating, updating, deleting — raise an approval gate before they run, unless you've turned on auto-approval (off by default). For writes, the server mints a one-time, server-side proof-of-approval token bound to your account and the specific tool, so a write can't be slipped through by bypassing the popup.

Artifacts

An MCP step can save its result as an artifact labeled "Integration" into your project folders, just like role steps save their labeled outputs.