01 / Foundations
How to scope a vertical slice
A vertical slice is the smallest version that proves the merge is playable. It is not a short roadmap; it is a complete loop with a start, decision, result, failure state, and reset.
The problem to solve
A feature list hides the most important unknown: whether the two systems feel coherent during play instead of only in a design document.
Write the expected behavior before changing a game directory or adding a new dependency. A precise failure statement helps you choose a smaller test and prevents a tool from becoming a collection of unrelated experiments.
A practical method
Write one sentence for the player action, one sentence for the imported rule, and one sentence for failure. Remove every feature that does not change that test.
Keep the base loop, input contract, and save boundary visible. Use original placeholders and a reversible local test whenever the workflow touches game files or generated assets.
How to verify the result
Ask a fresh tester to complete the slice without explaining the implementation. Their confusion reveals missing feedback faster than another architecture diagram.
Record the engine or tool version, the exact steps, the observed result, and the recovery path. A problem article is useful when another reader can reproduce the check without guessing what changed.
101 / Quick answers
Common How to scope a vertical slice questions
001How small should the first slice be?+
Small enough to complete in one room or route and repeat after a failure without rebuilding the world.
002What should the first test include?+
One controlled scenario, one expected result, and one reset or restore path. Expand only after that scenario is repeatable.
003What should I document?+
Document the base game or tool version, required ownership, files changed, expected output, and the safe way to undo the experiment.
004What should I avoid?+
Avoid distributing proprietary files, bypassing ownership or anti-cheat checks, and making irreversible changes before a backup and a small test exist.
FAQ
FAQ
How small should the first slice be?+
Small enough to complete in one room or route and repeat after a failure without rebuilding the world.
Can I solve this with a larger prompt?+
Usually not. A smaller prompt tied to one reproducible failure produces a more useful implementation and a clearer review.
Where can I continue?+
Continue with pass through mod explained or engine compatibility or save state and reset and compare the linked workflow before expanding scope.
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