Check Status Before JSON

A JSON error envelope is still an unsuccessful HTTP response. Code that decodes first can accidentally treat {"error": ...} as ordinary catalog data.

Replace the temporary status read in request_json with the status boundary:

    response.raise_for_status()
    return response.json()

The order is the contract. A 200 reaches json(). /items/99, the deliberate /scenarios/not-found, and /scenarios/server-error raise HTTPError before their bodies can be mistaken for success.

Do not catch anything inside request_json. It cannot decide what a command should print or which exit status the caller needs. At a command boundary, the narrow pattern is:

try:
    document = request_json("/items/99")
except requests.HTTPError as exc:
    print(exc.response.status_code)

Read the status from exc.response.status_code, not from exception text. The capstone will turn that value into one stable user-facing message. Unrelated programming defects must still escape with their traceback.

Try both routes against the live internal service if you want to see the real thing. Then write the fake-response version, because that is the one that will still behave identically in six months on a machine with no network.

If the ordering rule feels arbitrary, ask Monty to show what happens when a 404’s JSON body gets decoded as though it were a successful page. Seeing the wrong data arrive successfully is more convincing than the rule.