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Hands-on with ZCode · Challenge 04 · 中文版

Lesson 4: Verify like a reviewer, not a spectator

Checkpoint l0410 ptsgated by test suiteZCode desktop app

Green tests are the floor, not the ceiling — run both suites, walk the scenario skins, and review the accumulated Git diff the way you would review a colleague's.

Six agent-tool courses share this challenge. ZCode desktop app-specific steps are still being written — until they land and pass review, this page defers its canonical to the primary course's copy.

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

Read https://flypython.com/skills/flypython/SKILL.md and start the FlyPython course `hands-on-with-zcode`.

Lesson 4: Verify like a reviewer, not a spectator

Objective

Both suites pass, and you hold a written record of what the green runs do and do not prove — plus a reviewed diff you would defend to a colleague.

Why this lesson exists

“All tests pass” is where most AI-assisted work stops — and where most silent bugs start. A suite proves the contract lines it asserts; it says nothing about the rows nobody wrote a test for. Verification is a report you write, not a feeling you have. ZCode keeps verification next to the work: the same workspace shows the Git state, the task list, and the terminal output — and remote control lets you check status or send an instruction from your phone while the desktop keeps running the work.

The lesson

Run the full pair in the workspace terminal:

python verify.py starter     # the implementation you supervised
python verify.py solution    # the reviewed reference

Both green means the contract is satisfied as written. Now do the review the suite cannot do for you:

  1. Walk a skin end-to-end. Pick a scenario/<skin>/ folder and run the tool on it: python starter/report_tool.py scenario/<skin>. Read the produced report against the input file — recompute one group total by hand.
  2. Review the accumulated diff. The workspace Git state shows every hunk that landed across the goal. Read it top to bottom. Every hunk should map to a contract line you named in Lesson 2. Anything that does not is scope creep — revert or justify it.
  3. Check the edges the tests skip. Feed the tool an empty CSV, a CSV with only invalid rows, a missing file. The contract does not pin these — your judgment does. Write down what it does.

Exercise

Write the three-line evidence record for this change:

  • Verified: the commands you ran and what they proved.
  • Not verified: the inputs and behaviors no test pins.
  • Known limits: anything you saw that the contract never promised.

Keep it honest — “not verified” is a list of facts, not a confession.

Checkpoint

Run python verify.py. This checkpoint’s code prints only when both suites pass. You pass the lesson when you can answer:

  1. What did your by-hand recompute of a group total show?
  2. Name one input the suite does not pin and what the tool does with it.
  3. Which hunk, if any, would you ask a colleague to justify?

Expected evidence

Both green runs, your three-line evidence record, and the diff review notes.

Hints

Stuck? Open one at a time.

Hint 1 — What this checkpoint tests

That starter AND solution both pass — verify.py prints this code only when both suites are green. The gate is the pair, not a single run.

Hint 2 — Review the delta, not the vibes

The workspace Git state shows the whole accumulated change in one place — even from your phone via remote control. Read it as a reviewer: every hunk maps to a contract line, nothing extra moved, no test weakened.

Hint 3 — When you are done

You have written three evidence lines — verified / not verified / known limits — and could defend the change in a code review.

Submit

Done? Record it.

The 8-character code verify.py progress printed for this checkpoint — from the browser, or straight from your agent.

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 "Hands-on with ZCode" (course id course-zcode), checkpoint l04.
Machine-readable brief: https://flypython.com/api/challenges/hands-on-with-zcode
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 with python verify.py until its gates pass, then report each claim code to me.
Target: solve only checkpoint l04, 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":"hands-on-with-zcode","checkpoint":"l04","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/hands-on-with-zcode/files; you download nothing by hand. Prefer reading the source? Browse the folder on GitHub ↗