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Custom Tool

The Custom Tool lets you define your own tool — a named action with a set of inputs and a small function that runs when the agent (or flow) calls it. Use it when no built-in tool fits: custom business logic, a multi-step API call, a calculation, or anything you'd rather script once and reuse.

You create the tool once in Flowera's Tools area, then select it here to drop it into any flow.

Adding it to a flow​

In the Tool node's tool picker, choose Custom Tool, then pick one of the tools you've defined from the Select Tool dropdown.

Setup: create the tool first​

Before it appears in the dropdown, define the tool in Flowera's Tools area. A custom tool has:

  • Name — what the agent sees and calls (e.g. check_inventory).
  • Description — tells the agent when to use it. Write this clearly; it's how the agent decides.
  • Schema — the inputs the tool accepts (name, type, whether required). The agent fills these in.
  • Function — the code that runs. It receives the inputs and returns a result. Your custom variables are available inside it.
tip

The schema is what makes the tool reliable. Give each input a clear name and description so the agent provides the right values.

Inputs​

ParameterDescriptionRequired
Select ToolThe custom tool (defined in the Tools area) to use.Yes
Return DirectSend the tool's output straight back to the user instead of feeding it back to the agent.No

Outputs​

The tool returns whatever your function returns. It's a single-output tool — the flow continues to the next node. With Return Direct enabled, the output goes directly to the user as the reply.

Example​

Check stock for a product

  1. In the Tools area, create a tool named check_inventory with one input, sku (string, required), and a function that calls your inventory API and returns the count.
  2. In a flow, add an Agent node and give it the Custom Tool, selecting check_inventory.
  3. When a customer asks "is X in stock?", the agent calls the tool with the SKU and answers with the result.

Tips​

  • Write a strong description. The agent chooses tools by their descriptions — vague descriptions lead to the tool being skipped or misused.
  • Keep inputs minimal. Fewer, well-named inputs make the tool easier for the agent to call correctly.
  • Use Return Direct when the tool already produces the exact user-facing answer and you don't need the agent to rephrase it.
  • Reuse across flows. A tool defined once shows up in every flow's Custom Tool dropdown.