Build against a contract with Copilot

Tool: VS Code + GitHub Copilot (agent mode)

The Code altitude hands you a contract, not a solution: stubs, TODOs, and docstrings that say what to build, not how. Your job is to finish them - and the fastest way is to let Copilot agent mode write the code with you.

Steps

1. Open the stub the build page points you at. Read the note at the top - it spells out, in plain English, exactly what it must take in and hand back.

2. Open Copilot Chat in agent mode in VS Code. It can see the whole repo - the stub, the library it calls, and the examples nearby.

3. Point it at that one stub and ask it to finish it:

   Finish check_content.py so it matches the contract in its docstring.
   Use the existing helpers; don't invent new ones.

4. Run it. Read what came back against the contract - does it produce the shape the app expects?

5. Fix one thing at a time. Correct the prompt or the code, re-run, repeat.

You'll know it worked when... the stub is done and the app uses it - a "not wired" marker turns into a real result.

Layers, not one big prompt

Get one stub working end to end before the next. Small, verifiable steps beat a single prompt that half-works in five places.

Apply it to your scenario

Decide what each piece should prove or produce; let Copilot handle the syntax. Keep guardrails in the code - a check that fails loudly - not just in the prompt.