Level 5: Chat with your documents (RAG), tools and AI agents

import math
import re
from collections import Counter

documents = {
    "fees": "School fees are KSh 18,000 per term, payable by M-Pesa Paybill 400200, account: student number.",
    "intake": "We admit new students in January, May and September. Applications close two weeks before each intake.",
    "transport": "School buses serve Thika town, Ruiru and Juja. Transport costs KSh 6,000 per term.",
    "uniform": "Uniforms are sold at the school shop. A full set costs KSh 4,500.",
}

STOP = {"the", "a", "is", "are", "and", "of", "per", "do", "you", "what", "how", "much", "in", "to", "we", "by"}

def tokens(text):
    return [w for w in re.findall(r"[a-z0-9]+", text.lower()) if w not in STOP]

def similarity(q, d):
    qa, da = Counter(tokens(q)), Counter(tokens(d))
    dot = sum(qa[w] * da[w] for w in qa)
    norm = math.sqrt(sum(v * v for v in qa.values())) * math.sqrt(sum(v * v for v in da.values()))
    return dot / norm if norm else 0.0

def retrieve(question, k=2):
    ranked = sorted(documents.items(), key=lambda kv: similarity(question, kv[1]), reverse=True)
    return [(name, text) for name, text in ranked[:k] if similarity(question, text) > 0]

def build_prompt(question):
    chunks = retrieve(question)
    context = "\n".join(f"[{name}] {text}" for name, text in chunks) or "(no relevant documents found)"
    return ("Answer the parent's question using ONLY the information below. "
            "If the answer is not there, say you are not sure.\n\n"
            f"Information:\n{context}\n\nQuestion: {question}")

print(build_prompt("How much is transport per term?"))
print("=" * 50)
print(build_prompt("When is the next intake?"))

User: "Has order 1042 been delivered?"
AI → asks to call: check_order_status(order_id="1042")
Your code → looks it up in your database → "Out for delivery, rider: Otieno, ETA 3pm"
AI → "Your order 1042 is on its way with Otieno and should arrive around 3 pm."

import re

orders = {"1042": "Out for delivery, rider Otieno, arriving about 3pm", "1043": "Delivered yesterday"}

def check_order_status(order_id):
    return orders.get(order_id, "No order with that number")

TOOLS = {"check_order_status": check_order_status}

def pretend_model(user_message):
    # A real model decides this itself from the tool descriptions you give it
    m = re.search(r"\border (\d+)", user_message.lower())
    if m:
        return {"tool": "check_order_status", "args": {"order_id": m.group(1)}}
    return {"reply": "Please share your order number."}

def handle(user_message):
    decision = pretend_model(user_message)
    if "tool" in decision:
        result = TOOLS[decision["tool"]](**decision["args"])       # your code runs the tool
        return f"(tool said: {result}) -> AI writes a friendly reply from this"
    return decision["reply"]

for msg in ["Has order 1042 been delivered?", "Where is my parcel?", "Status of order 9999"]:
    print(msg, "\n  ", handle(msg))