09 State what is fixed, or it invents structure

What people usually ask

Design a test matrix to optimize extraction yield.

What comes back

A full factorial with a screening phase, three variables nobody named, starting levels nobody chose, and a pre study before the real work can begin.

Ask this instead

I am planning extraction runs on a ground solid feed and need a test matrix.
Fixed, not open to change: the solvent is <solvent>; one 2 L jacketed vessel; one pump; the bath gives three temperatures only, <T1>, <T2> and <T3> C.
Vary only two things: extraction time (30, 60 or 120 minutes) and solvent to solid ratio (5, 10 or 15 to 1).
No phases, no screening study, no pre study, no variable beyond the two named. At most 12 runs.
Return one table: run number, temperature, time, ratio, and a last column with the reason that row is in the matrix. If you want a row that needs a level not listed here, leave it out and say so under the table.

Attach: A list of the equipment that exists and what cannot change, pasted above the prompt.

Why it works: The assistant fills every gap with structure of its own, so naming what is fixed closes the gaps before it starts.