Give your agent tools with MCP (Python) · Challenge 05

Expose one real tool to your agent

Checkpoint l0510 ptsself-reported — code from verify.pyClaude Code 2.x (protocol: MCP 2026-07-28)

Wrap one function you actually own behind the validated, isolated boundary you just built.

Doing this with your agent? One sentence starts the whole course:

Read https://flypython.com/skills/flypython/SKILL.md and start the FlyPython course `mcp-server-in-python`.

Expose one real tool to your agent

Objective

Wrap one function you actually own behind the validated, isolated boundary you just built.

The lesson

Pick one read-only function from your own project — a lookup, a summary, a calculation. Register it as a tool with an explicit schema, reuse the validation and isolation patterns, and write its failure tests before wiring any client. The 2026-07-28 migration guide covers moving existing servers; this lesson is your first tool done right.

Exercise

Start with the failure tests; the schema is the contract
Record what you did not verify (client compliance, transport behavior)

Checkpoint

The lesson’s commands run, and you can answer these in your own words (the agent asks; you answer — that is the gate):

Which command did this lesson run, and what did it decide?
What failed at the start, and why — in your own words?
Before trusting a similar change next time, what would you check first?

Expected evidence

The command transcript and your answers.

Hints

Stuck? Open one at a time.

Hint 1 — What this checkpoint tests

Exposing one real tool: wrap a function you own behind the validated, isolated boundary you just built.

Hint 2 — Schema honestly

Give the tool a real inputSchema naming required arguments — the boundary only earns trust if the schema tells the truth.

Hint 3 — The honest record

Note what your tool may and may not do — a schema that overclaims defeats the isolation you just proved.

Submit

Done? Record it.

Use the 8-character code printed by python verify.py. For a self-reported checkpoint, answer the lesson questions first, then run python verify.py --attest l05.

Youbrowser

Submit the claim code

Your agentauto-submit

Let the agent solve and submit

Hand it this checkpoint (copy button on hover) — it solves, verifies, and submits on its own:

Work on the FlyPython challenge "Give your agent tools with MCP (Python)" (course id course-mcp-tools), checkpoint l05.
Machine-readable brief: https://flypython.com/api/challenges/mcp-server-in-python
Open the course folder and read TASK.md first — it is the contract.
Rules: smallest change, no new dependencies, never edit tests/ or solution/.
Check starter/ with python verify.py; ask me the lesson questions before using --attest ID for any self-reported checkpoint.
Target: solve only checkpoint l05, and submit it as soon as it passes.

With a token from your agent page (env FLYPYTHON_TOKEN), it records the result directly:

curl -X POST https://flypython.com/api/claims \
  -H "Authorization: Bearer $FLYPYTHON_TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"claims":[{"course":"mcp-server-in-python","checkpoint":"l05","code":"<8-char code>"}]}'

Or install the full FlyPython agent skill once and skip the paste.

Files

The starter and verifier

Solving runs on your machine — your agent fetches the course files itself via /api/challenges/mcp-server-in-python/files; you download nothing by hand. Prefer reading the source? Browse the folder on GitHub ↗