yuumi-design

name	yuumi:design
description	Agree on domain, package location, responsibility, and function signatures before implementing — sketch the skeleton, record a design note, hand off code to yuumi:implement. Invoke by hand.
version	1.6.4
disable-model-invocation	true
argument-hint	["what to build"]

Skeleton first

Jump straight to code and the domain, location, and responsibility questions get argued after the fact — you finish the code, then ask "which module does this belong in?" or "should this merge with the existing class?". This skill settles the skeleton before a line of code is written.

The hard guard

This skill creates and edits no source files. Its only output is one design note, and the skeleton lives as signature sketches — code blocks — inside that note.

If you created or edited a source file, you broke this skill.

The real code comes later, in step 5, from yuumi:implement.

Steps

1. Scope and dependency direction

Find what $1 touches: the modules and domains involved, the naming and patterns already there. Settle the dependency direction first — if module A cannot reference B, code that uses A cannot live in B, so direction fixes location before anything else. Misplacing code is the most expensive rework.

• Done when: you can name, in one line, the module the new code lands in and its dependency direction.

2. Present the four axes as one recommended design

Do not interrogate the axes one at a time. Put one coherent recommendation on the table and mark only the genuine forks:

• Domain — which bounded context it belongs to
• Package location — which module/package, grounded in step 1's dependency direction
• Responsibility — the new class's single responsibility; merge into an existing class or split
• Function signatures — input/output types, dependencies

Reach for domain-modeling when the domain terms are fuzzy, codebase-design when module seams or interface depth are the question.

Then confirm the forks in a single batched AskUserQuestion — not one per axis — and let the user correct the deltas.

• Done when: all four axes are settled on one choice each.

3. Approve the skeleton sketch

Draw the agreed structure as signature sketches: class and interface declarations, package paths, dependencies, function signatures. No bodies — // TODO or a one-line intent. Show it; get approval.

• Done when: the user approves the skeleton.

4. Record the design note

Write the settled decisions to tasks/yyyy-MM-dd-<topic>-design.md: the four-axis choices, the skeleton sketch, and the one or two tradeoffs worth tracing later. Keep it short.

• Done when: the file exists.

5. Hand off to yuumi:implement

Pass the design note to yuumi:implement as its input, so these decisions flow into that skill's implementation note. This skill stops here — it does not implement.