/improve-architecture

name: improve-architecture
description: Audit an area of the codebase and propose the smallest structural moves that improve it - untangle boundaries, kill duplication, fix seams, break cycles. Produces a prioritized plan and decision records, not a rewrite. Use when a codebase feels tangled, hard to change, or is becoming a ball of mud, or when asked to improve or refactor architecture.
user-invocable: true

improve-architecture

Invest in the shape of the system a little at a time rather than paying for a rewrite later. This skill diagnoses and proposes; it does not rewrite on its own.

Method

1. **Map first.** Get the current shape before judging it - entry points, modules, data flow, who calls whom. Reuse `module-map` for the one-screen view; do not skip to opinions. 2. **Find the strain.** Look for the load-bearing problems, not style nits:

• God modules that everything imports and nothing can change safely.
• Leaky boundaries - a module reaching into another's internals instead of

its surface.

• Duplicated logic that drifts (the same rule implemented three ways).
• Wrong seams - the code is split where it does not bend and fused where it

does.

• Cyclic dependencies.
• A shape that fights the domain (see `domain-modeling` - boundaries in code

should track boundaries in the language). 3. **Propose the smallest move.** For each problem, the least change that relieves it: extract a boundary, collapse a duplicate, invert a dependency, move a seam. Prefer a sequence of safe steps over one big cut. 4. **Rank by leverage.** Order the moves by pain relieved over effort. Say which are safe now and which need a test net first (pair with `tdd`). 5. **Record the big calls.** For a structural change a future reader would question, write a decision record in `docs/decisions/NNNN-slug.md`: context, choice, alternatives rejected, why.

Guardrails

• Diagnose, do not rewrite. The deliverable is a plan the user approves before

any code moves.

• No churn for taste. A move must relieve a named strain; "cleaner" is not a

reason.

• Three similar lines beat a premature abstraction - do not trade duplication

for indirection unless the duplication actually drifts.

• Keep behavior fixed. Structural moves are refactors; land them behind green

tests.

Output

A prioritized list: each item is the problem, the smallest move, the risk, and whether it needs a test net first. Plus decision records for the big moves. No code changes until the user picks what to do.