AI Agent1 input → 1 output

AI Tool (Function)

Creates a JavaScript function-based tool that the AI Agent can call to execute custom logic.

Inputs

payload any: Message from upstream node
aiagent object: AI configuration passed through the flow

Outputs

Output 1 - To Next Node

payload any

Original payload passed through

aiagent.tools array

Updated tools array with this function tool added
Output 2
Not used during initial message pass. Function executes inline when AI calls the tool.

Details

Function tools let you write custom JavaScript that the AI can invoke. Perfect for:

Data transformations
Calculations
Calling external APIs
Database operations

Configuration

Tool Name

Unique identifier (letters, numbers, underscores, hyphens only)

Description

Tell the AI what this function does

Function Code

JavaScript code to execute. Has access to:

input - Arguments provided by the AI
context - Node-RED context object
node - The Node-RED node instance

Examples

Calculate Age:

// Tool: calculate_age
// Description: Calculate age from date of birth
const dob = new Date(input.dateOfBirth);
const today = new Date();
const age = today.getFullYear() - dob.getFullYear();
return { age: age };

Format Currency:

// Tool: format_currency
const amount = parseFloat(input.amount);
const formatted = new Intl.NumberFormat('en-US', {
  style: 'currency',
  currency: 'USD'
}).format(amount);
return formatted;

Best Practices

Use new Date() instead of Date()
Always return a value (AI receives this as tool result)
Handle errors gracefully with try/catch
Keep functions focused on single tasks

// Tool: calculate_age // Description: Calculate age from date of birth const dob = new Date(input.dateOfBirth); const today = new Date(); const age = today.getFullYear() - dob.getFullYear(); return { age: age };