Custom Nodes

Overview

This guide will walk you through the process of creating a custom node for AnswerAI. We'll be building a simple Calculator tool as an example. Custom nodes can only be deployed to AnswerAI if you self host.

Prerequisites

• Git installed on your system
• AnswerAI repository cloned locally
• Familiarity with TypeScript and Node.js

Step 1: Set Up the Project Structure

1. Navigate to the packages/components/nodes/tools directory in your AnswerAI project.
2. Create a new folder named Calculator.

Step 2: Create the Base Class

1. Inside the Calculator folder, create a new file named Calculator.ts.
2. Add the following code to Calculator.ts:

import { INode } from '../../../src/Interface'
import { getBaseClasses } from '../../../src/utils'

class Calculator_Tools implements INode {
    label: string
    name: string
    version: number
    description: string
    type: string
    icon: string
    category: string
    author: string
    baseClasses: string[]

    constructor() {
        this.label = 'Calculator'
        this.name = 'calculator'
        this.version = 1.0
        this.type = 'Calculator'
        this.icon = 'calculator.svg'
        this.category = 'Tools'
        this.author = 'Your Name'
        this.description = 'Perform calculations on response'
        this.baseClasses = [this.type, ...getBaseClasses(Calculator)]
    }
}

module.exports = { nodeClass: Calculator_Tools }

Understanding the Properties

Property	Description
label	The name of the node that appears on the UI
name	The name used by code (must be camelCase)
version	Version of the node
type	Usually the same as label, defines which node can be connected to this specific type on UI
icon	Icon of the node
category	Category of the node
author	Creator of the node
description	Node description
baseClasses	The base classes from the node, used to define which node can be connected to this node on UI

Step 3: Define the Core Functionality

1. Create a new file named core.ts in the Calculator folder.
2. Add the following code to core.ts:

import { Parser } from 'expr-eval'
import { Tool } from '@langchain/core/tools'

export class Calculator extends Tool {
    name = 'calculator'
    description = `Useful for getting the result of a math expression. The input to this tool should be a valid mathematical expression that could be executed by a simple calculator.`

    async _call(input: string) {
        try {
            return Parser.evaluate(input).toString()
        } catch (error) {
            return "I don't know how to do that."
        }
    }
}

This class defines the actual functionality of our Calculator tool.

Step 4: Finalize the Node Class

1. Update Calculator.ts to include the initialization function:

import { INode } from '../../../src/Interface'
import { getBaseClasses } from '../../../src/utils'
import { Calculator } from './core'

class Calculator_Tools implements INode {
    // ... (previous code remains the same)

    async init() {
        return new Calculator()
    }
}

module.exports = { nodeClass: Calculator_Tools }

The init function will be called when the flow is executed, and the _call function will be executed when the language model decides to use this tool.

Step 5: Enable Community Nodes

1. Open the .env file in the packages/server directory.
2. Add the following line:

SHOW_COMMUNITY_NODES=true

This allows AnswerAI to recognize and use your custom node.

Step 6: Build and Run

1. In the root directory of your AnswerAI project, run:

pnpm build

2. Once the build is complete, start AnswerAI:

pnpm start

3. Open the AnswerAI interface in your browser. You should now see your Calculator node available in the Tools category.

Calculator Node & Drop UI

Troubleshooting

• If your node doesn't appear, ensure that SHOW_COMMUNITY_NODES is set to true in your .env file.
• Check the console for any error messages during the build or start process.
• Verify that your node's files are in the correct directory structure.

Next Steps

• Consider adding more complex functionality to your Calculator tool.
• Explore creating nodes for other categories, such as Memory or Chains.
• Share your custom node with the AnswerAI community!

Remember to test your node thoroughly to ensure it interacts correctly with other components in AnswerAI flows.