Any MCP connection you have active — Custom or from the catalog — also shows up as a piece in the **Flows builder** (Manual 55 · Jobs and Flows), so a flow can use its tools as just another step, with no conversation involved. **Requirements:** Admin or Editor role (the same one that edits flows); at least one MCP connection with some tool active. 1. In the builder's piece palette, look for the **"MCP servers"** section — one card per connection, with its real name and how many tools it has active ("N tools"). 2. Drag the card for the connection you want to use onto a flow step. 3. In the step's inspector, pick the specific **tool** from the dropdown — only the ones you have active for that connection show up (sections 5-6). 4. Fill in the **arguments**: the form generates itself, based on what that tool actually expects, with the label and the help text the provider itself describes for each field. If you switch tools, the arguments reset to the new one's defaults. If you don't have any connection with active tools yet, the section shows a notice instead of the empty palette: "Connect an MCP server to use its tools in your flows.", with a direct link to **Settings › MCP servers**. > **Important — If the tool stops being available when the flow runs** > > Between the time you build the flow and the moment it actually runs, the connection may have been > disconnected or the tool may have been turned off. In that case, the step fails with a clear notice in > the run's history ("The MCP server or the tool is no longer available. Check the connection in > Settings."), with a direct link to Settings — it never runs halfway or makes up a result. If it's the > arguments that no longer match what the server expects, the notice is "The data sent to the MCP tool no > longer matches what the server expects." — in both cases, review the connection or the step and save > again.