Review and Simplify Changes

When to Use

Use this skill when you need review a git diff or explicit file scope for reuse, code quality, efficiency, clarity, and standards issues, then optionally apply safe Codex-driven fixes. Use when the user asks to "simplify code", "review changed code", "check for code reuse", "review code quality", "review...

Review changed code for reuse, quality, efficiency, and clarity issues. Use Codex sub-agents to review in parallel, but keep those sub-agents read-only: they should only inspect code and send findings back to the main agent. Only the main agent may apply high-confidence, behavior-preserving fixes.

Modes

Choose the mode from the user's request:

• review-only: user asks to review, audit, or check the changes
• safe-fixes: user asks to simplify, clean up, or refactor the changes
• fix-and-validate: same as safe-fixes, but also run the smallest relevant validation after edits

If the user does not specify, default to:

• review-only for "review", "audit", or "check"
• safe-fixes for "simplify", "clean up", or "refactor"

Step 1: Determine the Scope and Diff Command

Prefer this scope order:

1. Files or paths explicitly named by the user
2. Current git changes
3. Files edited earlier in the current Codex turn
4. Most recently modified tracked files, only if the user asked for a review but there is no diff

If there is no clear scope, stop and say so briefly.

When using git changes, determine the smallest correct diff command based on the repo state:

• unstaged work: git diff
• staged work: git diff --cached
• branch or commit comparison explicitly requested by the user: use that exact diff target
• mixed staged and unstaged work: review both

Do not assume git diff HEAD is the right default when a smaller diff is available.

Before reviewing standards or applying fixes, read the repo's local instruction files and relevant project docs for the touched area. Prefer the closest applicable guidance, such as:

• AGENTS.md
• repo workflow docs
• architecture or style docs for the touched module

Use those instructions to distinguish real issues from intentional local patterns.

Step 2: Launch Four Read-Only Review Sub-Agents in Parallel

Use Codex sub-agents when the scope is large enough for parallel review to help. For a tiny diff or one very small file, it is acceptable to review locally instead.

When spawning sub-agents:

• give each sub-agent the same scope
• tell each sub-agent to inspect only its assigned review role
• tell each sub-agent it is operating in a read-only review pass
• do not let sub-agents edit files, run apply_patch, stage changes, commit, or perform other state-mutating actions
• ask for concise, structured findings only
• ask each sub-agent to report file, line or symbol, problem, recommended fix, and confidence
• ask each sub-agent to return findings to the main agent only; they must not implement fixes themselves

Use four review roles.

Sub-Agent 1: Code Reuse Review

Review the changes for reuse opportunities:

1. Search for existing helpers, utilities, or shared abstractions that already solve the same problem.
2. Flag duplicated functions or near-duplicate logic introduced in the change.
3. Flag inline logic that should call an existing helper instead of re-implementing it.

This sub-agent is read-only. It must not edit files, apply patches, or make any other workspace changes.

Recommended sub-agent role: explorer for broad codebase lookup, or reviewer if a stronger review pass is more useful than wide search.

Sub-Agent 2: Code Quality Review

Review the same changes for code quality issues:

1. Redundant state, cached values, or derived values stored unnecessarily
2. Parameter sprawl caused by threading new arguments through existing call chains
3. Copy-paste with slight variation that should become a shared abstraction
4. Leaky abstractions or ownership violations across module boundaries
5. Stringly-typed values where existing typed contracts, enums, or constants already exist

This sub-agent is read-only. It must not edit files, apply patches, or make any other workspace changes.

Recommended sub-agent role: reviewer

Sub-Agent 3: Efficiency Review

Review the same changes for efficiency issues:

1. Repeated work, duplicate reads, duplicate API calls, or unnecessary recomputation
2. Sequential work that could safely run concurrently

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