A script driving a JSON-lines probe hangs when an answer is not an object

Symptoms

A driver script that talks to a game's probe (one command a line, one JSON answer a line) stops; the game process and the script both sit at 0% CPU.

Cause

The script skipped every line that did not start with { or [, to step over log lines. An answer can be any JSON value (null, a number, a string), so the script skipped the answer and waited for a line that never came, while the game waited for the next command (observed with Un-POD's probe, 2026-10-24).

What to do

Parse each line as JSON and treat any value as the answer; send log lines to stderr in the program so they never share stdout with answers.