1// Tool: Weather API
2// Agent Tool node configuration:
3// Name: get_weather
4// Description: "Get current weather for a city. Input: city name."
5
6// Connected to HTTP Request node:
7// URL: https://api.weatherapi.com/v1/current.json
8// Query: q={{ $json.query }}
9// API Key: configured in credential
10
11// Return format for agent:
12// Code node after HTTP:
13const data = $json;
14return {
15  json: {
16    result: `Weather in ${data.location.name}: ${data.current.condition.text}, Temperature: ${data.current.temp_c} celsius`
17  }
18};

1// Tool: Calculator
2// n8n Calculator Tool node (built-in)
3// Or custom code tool:
4
5// Name: advanced_calculator
6// Description: "Perform calculations. Supports: +, -, *, /, sqrt, power, percentage"
7
8// Code node implementation:
9function calculate(expression) {
10  // Safe math evaluation
11  const cleanExpr = expression.replace(/[^0-9+\-*/().%sqrt pow]/g, '');
12  
13  // Handle special functions
14  let result;
15  if (cleanExpr.includes('sqrt')) {
16    const num = parseFloat(cleanExpr.match(/\d+/)[0]);
17    result = Math.sqrt(num);
18  } else if (cleanExpr.includes('pow')) {
19    const nums = cleanExpr.match(/\d+/g);
20    result = Math.pow(parseFloat(nums[0]), parseFloat(nums[1]));
21  } else {
22    result = Function('"use strict"; return (' + cleanExpr + ')')();
23  }
24  
25  return { result: result.toString() };
26}
27
28return { json: calculate($json.query) };

1// Sub-workflow as tool
2// 1. Create separate workflow
3// 2. Start with "Execute Workflow Trigger" node
4// 3. Add your complex logic
5// 4. End with return data
6
7// In Agent workflow:
8// Add "Call n8n Workflow" tool
9// Select the sub-workflow
10// Agent will call it when needed

1// Name: web_scraper
2// Description: "Fetch and extract text content from a web URL"
3
4// HTTP Request node:
5// URL: {{ $json.url }}
6// Response Format: Text
7
8// Code node: Extract clean text
9const html = $json.data;
10
11// Simple text extraction
12const text = html
13  .replace(/<script[^>]*>[\s\S]*?<\/script>/gi, '')
14  .replace(/<style[^>]*>[\s\S]*?<\/style>/gi, '')
15  .replace(/<[^>]+>/g, ' ')
16  .replace(/\s+/g, ' ')
17  .trim()
18  .substring(0, 3000); // Limit length
19
20return { json: { content: text, url: $json.url } };

1// Name: spreadsheet_manager
2// Description: "Read, write, or search data in Google Sheets"
3
4// Google Sheets node configuration:
5// Operation: {{ $json.operation }}
6// Sheet: {{ $json.sheetName }}
7
8// Agent can specify:
9// - operation: "read", "append", "search"
10// - sheetName: target sheet
11// - data: rows to write
12// - searchKey: what to search for

1// Name: send_email
2// Description: "Send an email. Requires: to, subject, body"
3
4// Gmail node:
5// To: {{ $json.to }}
6// Subject: {{ $json.subject }}  
7// Body: {{ $json.body }}
8
9// Important: Always require AI to confirm before sending
10// Add confirmation step in workflow

1// Good tool description - Agent knows when to use it
2const goodDescription = "Search company knowledge base for HR policies, benefits, and employee guidelines. Input: search query about HR topics.";
3
4// Bad tool description - Too vague
5const badDescription = "Search stuff.";
6
7// Tool input validation
8function validateInput(input, schema) {
9  const errors = [];
10  for (const [key, config] of Object.entries(schema)) {
11    if (config.required && !input[key]) {
12      errors.push(`Missing required field: ${key}`);
13    }
14    if (config.type && typeof input[key] !== config.type) {
15      errors.push(`${key} should be ${config.type}`);
16    }
17  }
18  return errors;
19}