Aif Improve

aif-improve

Find where the structure of working code makes it harder to test and change than it needs to be, and propose deepenings — changes that trade a pile of shallow modules for a smaller number of deep ones. Every candidate carries evidence; no code changes until you pick one.

Principles: depth over extraction · evidence over taste · propose, don't touch.

This is not a diff review (that's aif-code-review) and not a task map (that's aif-recon). It reads existing code and asks a different question: where is the structure making this harder to understand, test, and change than it needs to be — and what deeper shape would fix it? aif-code-review may hand off paths to this skill via its non-blocking Deepening pointers footer — a review that kept bumping into pre-existing shallowness points here rather than restructuring inside a merge gate.

The lens is module depth (Ousterhout, A Philosophy of Software Design): a deep module hides a lot of behavior behind a small interface. See references/module-depth.md for the working vocabulary — use it exactly, so suggestions stay consistent.

Self-contained — built-ins only: git, Glob, Grep, Read, Bash, and (where available) the Task tool for parallel exploration. Read-only in steps 1–2; step 3 edits code only after you pick a candidate and agree the design.

Workflow

1. Explore        → read optional domain docs, then walk the code for friction   (orchestrator)
2. Present        → evidence-backed candidates, ranked; ask which to pursue        (orchestrator)
3. Deepen         → design the interface with the user, then implement one         (orchestrator)

1. Explore

Optional context first (only if present — never required):

• CONTEXT.md / a domain glossary → use its nouns to name modules (the "Order intake module", not

"the FooBarHandler"). If absent, name modules after what they do.

• docs/adr/ (or docs/decisions/) → decisions already made. Do not re-litigate a settled ADR;

only reopen one when the friction is real enough to warrant it, and say so explicitly.

Explorer: if the aif-recon skill is installed, use it to map the target area (pass the path or area, no --spec needed). Otherwise scout inline: Glob/Grep to size the space, then read the owners. On runtimes with the Task tool, fan out read-only Explore subagents over disjoint directories; otherwise sweep sequentially.

Read through the target area the way you would to make a change, and note friction as you hit it — don't grind a checklist:

• understanding one concept requires bouncing between many small modules (no locality);
• a module is shallow — its interface is nearly as wide as its implementation;
• pure functions were extracted only for testability, but the real bugs live in how they're called;
• tightly-coupled modules leak state or assumptions across their seam;
• a part of the codebase is untested, or can't be tested through its current interface.

Apply the deletion test (references/module-depth.md) to anything that smells shallow: paste it into its callers in your head. If nothing gets harder, it was decoration — the deepening candidate you want. If each caller inherits a copy of the hard part, it was already doing its job — leave it.

2. Present candidates

Do NOT design interfaces yet. Report per references/opportunity-report.md: each candidate as a card with the modules involved, the friction (concrete file:line evidence), the deletion-test result, the proposed deepening in plain English, the payoff in leverage + locality + test surface, a before→after sketch, and a recommendation-strength badge (Backed / Worth a look / Speculative). Carry over the evidence discipline from the review skill: every claim gets a [Verified] (a grep/count/test you ran, with output) or [Reasoned] tag, and any candidate whose value hinges on a fact you couldn't confirm gets a > Conditional: line.

End with a Top recommendation — which one to tackle first and why. Then ask the user: "Which of these would you like to pursue?"

With --html, also write the self-contained visual report (references/opportunity-report.md → HTML) to the temp dir and open it; markdown in chat stays the default.

3. Deepen a candidate

Once the user picks one, design the deeper module with them before writing code — see references/deepening-patterns.md. Walk the interface: the constraints, what sits behind the seam, which tests survive, what the caller no longer needs to know. Only cut a seam once a second implementation is present or clearly imminent — a seam with one thing plugged into it is a bet, not a need.

Side effects happen inline as the design settles, and only when the relevant doc already exists or the user opts in:

• Naming a module after a concept not in CONTEXT.md (and CONTEXT.md exists) → offer to add

the term, so the domain language and the code stay in sync.

• User rejects the candidate for a load-bearing reason (and docs/adr/ exists) → offer to record

an ADR, framed as "so future architecture reviews don't re-suggest this". Skip ephemeral reasons ("not now") and self-evident ones.

Then implement the agreed change. Verify through the new interface — run the tests that should still pass, and any new one the deepening makes possible. Never claim the refactor is done without running the proving command and reading its output (same verification gate as the review skill).

Input

| Invocation | Scans | |-----------|-------| | aif-improve | the whole repo (sampled — discloses coverage) | | aif-improve src/payments/ | a scoped path or area | | aif-improve "the auth flow" | an area named in prose (resolved to files first) | | … --html | also emit the visual before/after report to the temp dir |

For a whole-repo scan, disclose coverage honestly — "walked N of M modules, sampled by …" — and never imply exhaustiveness you didn't reach.

Tools used

Built-ins only: git, Glob, Grep, Read, Bash, plus the Task/Agent tool for parallel exploration where available, and Edit/Write in step 3 only. On Codex/Cursor, map these to that runtime's search / file-read / shell / edit equivalents — the capability is what matters, not the name. Prefers the aif-recon skill for exploration when installed; falls back to inline scouting.

References

• references/module-depth.md — the depth vocabulary (module, interface, depth, seam, leverage,

locality) + the deletion test and the principles that rank candidates.

• references/opportunity-report.md — the markdown candidate-card format, recommendation strength,

evidence rules, and the optional --html visual scaffold.

• references/deepening-patterns.md — common shallow→deep patterns and the interface-design walk for

step 3, plus the optional CONTEXT.md / ADR side-effects.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: ainative-build
• Source: ainative-build/skills
• License: MIT

Install and usage instructions live in the source repository linked above.