How does it know it's a question?

There's no trigger word. The rule is short:

1. TuxAide only looks at a line when the shell can't find its first word as a command. ls -la, git commit -m "how", your aliases and functions are never touched — the shell runs them as always.
2. Such a line is a question if it contains a question word — how, what, why, which, where, can I… in English, como, porquê, qual, onde… in Portuguese, and the same in Spanish, French and German — or ends with ?.
3. Right after a question, a short follow-up counts too: “and by size”, “e ao contrário”, “what about mac?”.

Anything else is a typo or a real “command not found”: TuxAide suggests a fix if it sees one (typos), and otherwise your shell (or your distro's handler) says what it always said.

Force a question

A question that starts with a real command is run as that command: find big files? runs find. Ask through tuxaide instead:

tuxaide find big files

Stop it

tuxaide off     # remembered in new terminals
tuxaide on

With TuxAide off, unknown commands get the shell's normal message and nothing is sent to the model.

Characters the shell treats specially

zsh would normally stop a line with an unmatched ? or * (no matches found) before TuxAide sees it. The hook turns zsh's NOMATCH option off in interactive shells, so what is this? works (an unmatched pattern is then passed on as typed, as in bash). In bash, avoid starting a question with ! (history expansion) — or ask through tuxaide "…".