At Simplify Agent Skill

Simplify

at-simplify → 4 cleanup agents in parallel → apply the fixes

You are improving the quality of the changed code, not hunting for bugs. Review

it for reuse, simplification, efficiency, and altitude issues, then fix what you

find. Do not look for correctness bugs — that is what at-review is for.

Phase 0 — Gather the diff

Run git diff "@{upstream}...HEAD" (or git diff main...HEAD / git diff HEAD~1

if there's no upstream) to get the unified diff under review. If there are

uncommitted changes, or the range diff is empty, also run git diff HEAD and

include the working-tree changes in scope — the review often runs before the

commit. If a PR number, branch name, or file path was passed as an argument,

review that target instead. Treat this diff as the review scope.

Phase 1 — Review (4 cleanup agents in parallel)

Launch 4 independent review agents using multi-agent capabilities, all in a

single message so they run concurrently. Pass each agent the diff and one of

the four angles below. Each returns its findings with file, line, a

one-line summary, and the concrete cost (what is duplicated, wasted, or

harder to maintain).

Reuse

Flag new code that re-implements something the codebase

already has — Grep shared/utility modules and files adjacent to the change,

and name the existing helper to call instead.

Simplification

Flag unnecessary complexity the diff adds: redundant or derivable state,

copy-paste with slight variation, deep nesting, dead code left behind. Name

the simpler form that does the same job.

Efficiency

Flag wasted work the diff introduces: redundant computation or repeated I/O,

independent operations run sequentially, blocking work added to startup or

hot paths. Also flag long-lived objects built from closures or captured

environments — they keep the entire enclosing scope alive for the object's

lifetime (a memory leak when that scope holds large values); prefer a

class/struct that copies only the fields it needs. Name the cheaper

alternative.

Altitude

Check that each change is implemented at the right depth, not as a fragile

bandaid. Special cases layered on shared infrastructure are a sign the fix

isn't deep enough — prefer generalizing the underlying mechanism over adding

special cases.

Phase 2 — Apply the fixes

Wait for all four agents to complete, dedup findings that point at the same

line or mechanism, and fix each remaining one directly. Skip any finding whose

fix would change intended behavior, require changes well outside the reviewed

diff, or that you judge to be a false positive — note the skip rather than

arguing with it. Finish with a brief summary of what was fixed and what was

skipped (or confirm the code was already clean).