🇫🇷 Version française

[!IMPORTANT] Every fixture, rulebook, and calculator output in this lab is synthetic and non-binding. Nothing here represents an actual Desjardins product, rate, or policy, and no regulator or insurer has reviewed or endorsed this material.

Overview

Item	Value
Duration	20 minutes
Level	Intermediate
Prerequisites	Lab 00

Learning Objectives

By the end of this lab, you will be able to:

• Explain why mcp/rulebook-server runs independently of apps/workshop and the agent, with no shared runtime
• Confirm the server exposes exactly one tool, get_rulebook(rulebook_id)
• Start the server locally and query it for the pinned rulebook ID and an unknown one
• Explain why the served rulebook always carries "authority": "WORKSHOP_AUTHORS_ONLY"

Exercises

Exercise 5.1: Read the Server

Open mcp/rulebook-server/main.py and mcp/rulebook-server/rulebook_data_loader.py. Note that get_rulebook compares the requested rulebook_id against the single pinned rulebook’s id field, RULEBOOK-SYN-ON, and returns an explicit {"rulebookId": ..., "error": "rulebook not found"} object for any other value.

Exercise 5.2: Run the Existing Tests

python -m pytest mcp/rulebook-server/tests -v

Expected result: every test passes, mirroring Lab 04’s coverage for the rulebook lookup.

Exercise 5.3 (Hands-on): Start the Server and Query It

python mcp/rulebook-server/main.py

The server listens on http://0.0.0.0:8002 by default. Leave it running, then in a second terminal, call it over MCP:

python -c "
import asyncio
from mcp import ClientSession
from mcp.client.streamable_http import streamablehttp_client

async def main():
    async with streamablehttp_client('http://localhost:8002/mcp') as (read, write, _):
        async with ClientSession(read, write) as session:
            await session.initialize()
            tools = await session.list_tools()
            print('tools:', [t.name for t in tools.tools])
            for rulebook_id in ('RULEBOOK-SYN-ON', 'RULEBOOK-DOES-NOT-EXIST'):
                result = await session.call_tool('get_rulebook', {'rulebook_id': rulebook_id})
                print(rulebook_id, '->', result.content[0].text)

asyncio.run(main())
"

Expected result: the pinned rulebook ID returns the full rulebook, including its baseCents, planAddOnCents, and the en-CA/fr-CA notice text. The unknown ID returns an explicit error field. The server console shows one get_rulebook(...) -> found or -> rulebook not found line per call. Stop the server with Ctrl+C when you are done.

Validation Checklist

• pytest mcp/rulebook-server/tests -v passes
• The pinned rulebookId returns the exact rulebook content
• An unknown rulebookId returns an explicit error result, not an exception
• You can state what "authority": "WORKSHOP_AUTHORS_ONLY" communicates to anyone reading this data

Knowledge Check

• Why does this server serve only one rulebook ID instead of a lookup table of many rulebooks?
• If a new rulebook version were pinned tomorrow, what would have to change in this server’s data file for get_rulebook to return it?

Next Steps

Continue to Lab 06: The LangGraph Agent.