📚 Function Calling Tutorial

1️⃣ Fundamentals

What is Function Calling?

Function calling (also called "tool use") is the ability to invoke external tools or APIs to perform actions beyond generating text. Instead of just answering with words, an AI can call functions with specific parameters.

Why Function Calling Matters

• Accuracy: Executes exact operations rather than describing them
• Integration: Connects AI with real systems
• Dynamic Responses: Adapts behavior based on tool results
• Reliability: Reduces hallucination by delegating to trusted tools

2️⃣ Core Concepts

A. Tool Definition

Every tool has three essential components:

Tool Name: weather_fetch
Purpose: Get current weather for a location
Parameters: latitude, longitude, location_name

B. Function Call Structure

A complete function call includes:

C. Parameter Types

Required Parameters (must always include):

• Authentication details
• Core identifiers
• Primary search terms

Optional Parameters (include when needed):

• Filters
• Format preferences
• Advanced options

Example:

Tool: places_search
Required: query (what to search for)
Optional: max_results (how many to return)
         location_bias_lat, location_bias_lng (where to search)

🎯 3️⃣ Tool Selection Strategy

Step 1: Understand the User's Need

Ask yourself: What action does the user want?

Step 2: Match to Available Tools

Create a mental checklist:

❓ Does this need real-time data? → Use fetch/search tools
❓ Does this need to show locations? → Use map tools
❓ Does this need to send information? → Use communication tools
❓ Does this need to display something? → Use visualization tools

Step 3: Verify Tool Capability

NOT appropriate to use a tool for:

• Questions answerable from general knowledge
• Tasks the tool wasn't designed for
• Requests requiring authentication you don't have

🔧 4️⃣ Payload Construction

A. Payload Anatomy

A payload is the data you send to a tool:

{
  "tool_name": "weather_fetch",
  "parameters": {
    "latitude": 48.8566,
    "longitude": 2.3522,
    "location_name": "Paris, France"
  }
}

B. Parameter Rules

C. Payload Construction Examples

{
  "queries": [
    {
      "query": "coffee shops Bangkok",
      "max_results": 5
    }
  ]
}

{
  "queries": [
    {
      "query": "luxury hotels Bali 3-star",
      "max_results": 8
    }
  ],
  "location_bias_lat": -8.6500,
  "location_bias_lng": 115.2167,
  "location_bias_radius": 10000
}

⚠️ 5️⃣ Common Mistakes to Avoid

{
  "data_type": "scores",
  "league": "nba"
}

💡 6️⃣ Practice Examples

Example 1: Weather Query

Question: "Is it raining in Singapore right now?"

{
  "tool": "weather_fetch",
  "parameters": {
    "location_name": "Singapore",
    "latitude": 1.3521,
    "longitude": 103.8198
  }
}

Example 2: Location Search & Display

Question: "Show me the top 3 coffee shops near my hotel in Kyoto on a map"

{
  "queries": [
    {
      "query": "coffee shops Kyoto",
      "max_results": 3
    }
  ],
  "location_bias_lat": 35.0116,
  "location_bias_lng": 135.7681
}

{
  "locations": [
    {
      "name": "Coffee Shop A",
      "latitude": 35.0150,
      "longitude": 135.7700,
      "place_id": "ChIJ...",
      "notes": "Cozy atmosphere, free WiFi"
    },
    {
      "name": "Coffee Shop B",
      "latitude": 35.0120,
      "longitude": 135.7680,
      "place_id": "ChIJ...",
      "notes": "Traditional Japanese cafe"
    },
    {
      "name": "Coffee Shop C",
      "latitude": 35.0100,
      "longitude": 135.7650,
      "place_id": "ChIJ...",
      "notes": "Modern roastery"
    }
  ]
}

Example 3: Sports Data

Question: "What was the final score of yesterday's NBA game between Lakers and Celtics?"

{
  "data_type": "scores",
  "league": "nba",
  "team": "Lakers"
}

🎓 7️⃣ Assessment Strategy

Before Attempting a Question

Use this checklist:

• Read the question completely
• Identify what the user actually wants (not what they said)
• List all available tools in your mind
• Eliminate tools that don't fit
• Verify required parameters
• Check parameter data types
• Confirm enum values (if applicable)
• Review your payload once more

During Question Solving

Common Assessment Traps

Final Assessment Tips

📖 Quick Reference: Common Tool Categories

Data Retrieval Tools

Visualization Tools

Communication Tools

File & Content Tools

🎯 Key Takeaway Formula

TOOL SELECTION = Match user need to tool capability
PAYLOAD CONSTRUCTION = Provide required parameters with correct types
SUCCESS = User gets exactly what they asked for

Remember: Precision > Creativity. Correctness > Cleverness.

🚀 Ready for Your Assessment?

You have all the tools you need. Trust your checklist. Go ace it! 💪