MCP Tool
Let an AI app call a workflow as a tool.
Start a workflow
When an AI app calls this tool
Publishes this workflow as an MCP tool. The AI app's arguments land on the trigger’s data, exactly like a form submission.
- Tool name · Optional
What the AI app calls it. Write it as an instruction: create_refund_for_customer, not workflow_3. Lowercase letters, digits and underscores; leave it blank to use the workflow's name. AI apps see it with a short suffix this workflow keeps for good (create_refund_for_customer_4f1ab9), so two workflows never share a name.
- What it does · Required
The AI app chooses this tool from this sentence alone. Say what it does, when to use it, and what it returns. A one-word description is a broken tool, and publishing refuses one.
- Parameters · Optional
What the AI app must supply. Each parameter's name becomes a key on {{trigger.body}}, the same shape a form submission produces.
- What to return · Optional
The name of the step whose output the AI app receives. Leave blank to return the last step's output.
For a step-by-step guide, see Turn your workflows into tools.
Not in your list? See When an app isn’t here.
For developers
In the API, which calls apps pieces, MCP Tool is pieceId: "mcptool". Its trigger is mcptool / mcp_tool. Get an app returns every field.