A well-formed prompt still works best on a task of the right size. This is how to cut a big ask down to that size.
Some things are just too big to hand over in a single prompt. Not because 3B can’t handle scale, it can, but because one instruction covering ten different things leaves you nowhere clean to stand when you want to check the work or fix the one part that came out off. The move is decomposition: breaking a big ask into smaller, ordered pieces that each do one thing you can recognize.
Structure the whole thing, build it in stages
If you’ve just come from Anatomy of a good prompt, this might sound like a contradiction. There, the advice was to give 3B the full structure of what you want. Here, it’s to build one piece at a time. So which is it?
Both, and they’re answering different questions. Structure is about describing a task completely: the order, the details, the limits. Decomposition is about what to do when the task is too big to be a single task at all. You still want 3B to understand the whole picture, what you’re ultimately building and how the parts fit together, so it’s not working blind. What changes is that you don’t ask it to construct all of that in one go. You give it the context up front, then build the pieces in sequence, each one a well-formed prompt in its own right. Context all at once; construction step by step.
Why smaller is easier to steer
When you ask for everything in one go and the result isn’t right, you’re left guessing which part let you down, so you re-prompt the whole thing and hope this run goes better. Build it in steps and each one gives you a result you can eyeball before moving on. A problem shows up where it actually happened, not three stages downstream wearing a disguise, and you fix that one step instead of rebuilding the lot.
How to find the seams
Big tasks almost always have natural break points, and they tend to sit wherever the work changes character. A few to watch for:
- A change in data. Raw input becomes something extracted, filtered, or reshaped. That’s a seam.
- A decision. Anywhere the path forks on a condition is its own step.
- An external action. Sending, creating, updating, or posting something is a clean unit of work.
- A handoff. Wherever one part’s output becomes the next part’s input, you’ve found a boundary.
Take “build an app that shows open requests, lets someone approve one, and updates its status.” That’s three tasks sharing a sentence: show the list, handle the approval, write the status back. Each is worth building and confirming before you wire them together.
Sequence, then connect
Put the steps in the order the work really flows, get each one producing what you expect, then join them up. If this feels familiar, it’s the same instinct as Mirror your manual steps, just aimed at prompting instead of planning. You’re not writing a smaller prompt, you’re writing a handful of right-sized ones that hand off to each other. The finished thing is exactly as big as it was always going to be. It’s just far less painful to get right, and far easier to fix when something drifts.
Next up: Common prompting mistakes, the usual suspects that trip people up, each with a quick fix.