Simple LLM Function Calling Example

import requests
import json
from duckduckgo_search import DDGS

# === Config ===
API_URL = "http://localhost:5000/v1/chat/completions"
API_KEY = ""
MODEL_NAME = ""
SYSTEM_PROMPT = (
    "You are an assistant that can perform function calls using search_duckduckgo({ \"query\": \"...\" }). "
    "Only use the function when the user asks for recent, location-specific, or online information. "
    "After the function is called, and relevant information is returned, continue the conversation using it.\n\n"
    "Examples:\n"
    "User: Who won the Oscar for Best Picture this year?\n"
    "Assistant: search_duckduckgo({ \"query\": \"2025 Best Picture Oscar winner\" })\n"
    "Assistant: The winner of Best Picture at the 2025 Oscars was The Midnight Star.\n\n"
    "User: What's the weather like in New York City?\n"
    "Assistant: search_duckduckgo({ \"query\": \"current weather in New York City\" })\n"
    "Assistant: It's currently 52°F and mostly cloudy in NYC, with winds around 10 mph.\n\n"
    "User: How do I reverse a string in Python?\n"
    "Assistant: You can reverse a string by using slicing: my_string[::-1]\n\n"
    "Begin."
)

# === Search Function ===
def duckduckgo_search(query, num_results=3):
    try:
        ddgs = DDGS()
        results = ddgs.text(query, max_results=num_results)
        return [
            {
                "title": r.get("title", "No title"),
                "link": r.get("href", "No link"),
                "snippet": r.get("body", "No snippet")
            }
            for r in results
        ]
    except Exception:
        return []

# === LLM Call ===
def call_llm(messages):
    headers = {"Content-Type": "application/json"}
    if API_KEY:
        headers["Authorization"] = f"Bearer {API_KEY}"  # Optional for local models

    payload = {
        "model": MODEL_NAME,
        "messages": messages,
        "temperature": 0.7,
        "max_tokens": 1000
    }

    response = requests.post(API_URL, headers=headers, json=payload)
    return response.json() if response.status_code == 200 else None

# === Extract Function Call ===
def extract_function_call(content):
    if "search_duckduckgo" in content:
        try:
            start = content.find('{')
            end = content.find('}', start)
            if start != -1 and end != -1:
                return json.loads(content[start:end+1])
        except Exception:
            pass
    return None

# === Main Loop ===
def main():
    history = [{"role": "system", "content": SYSTEM_PROMPT}]

    while True:
        user_input = input("\nUser: ")
        if user_input.lower() in {"exit", "quit"}:
            break

        history.append({"role": "user", "content": user_input})
        response = call_llm(history)
        if not response:
            continue

        message = response["choices"][0]["message"]
        content = message.get("content", "")
        function_args = extract_function_call(content)

        if function_args:
            query = function_args.get("query", "")
            results = duckduckgo_search(query)

            # Format result text for assistant use
            result_text = "\n\n".join(
                f"{r['snippet']} ({r['title']}, {r['link']})" for r in results
            )

            # Prepare list of sources for final output
            source_links = [f"{r['title']}: {r['link']}" for r in results]

            # Inject function call and results as assistant content
            history.append({"role": "assistant", "content": content})
            history.append({"role": "assistant", "content": result_text})

            # Request continuation with new knowledge
            followup = call_llm(history)
            if followup:
                final_message = followup["choices"][0]["message"]["content"]

                # Append sources at the end
                if source_links:
                    final_message += "\n\nSources:\n" + "\n".join(source_links)

                print(f"\n{final_message}\n")
                history.append({"role": "assistant", "content": final_message})
        else:
            print(f"\n{content}\n")
            history.append({"role": "assistant", "content": content})

if __name__ == "__main__":
    main()