---
name: simplify
description: Review changed code for reuse, quality, and efficiency — then fix any issues found.
tags: [review, quality, refactor, cleanup]
when_to_use: Use after finishing an implementation to catch duplication, hacky patterns, and inefficiencies before committing. Runs three parallel review agents then applies fixes.
argument_hint: [optional focus area, e.g. "focus on error handling"]
user_invocable: true
---

# Simplify: Code Review and Cleanup

Review all changed files for reuse, quality, and efficiency. Fix any issues found.

## Phase 1: Identify Changes

Run `git diff` (or `git diff HEAD` if there are staged changes) to see what changed. If there are no git changes, review the most recently modified files that the user mentioned or that you edited earlier in this conversation.

## Phase 2: Launch Three Review Agents in Parallel

Use `InvokeAgent` to launch all three agents concurrently in a **single message**. Pass each agent the full diff so it has complete context.

### Agent 1: Code Reuse Review

For each change:

1. **Search for existing utilities and helpers** that could replace newly written code. Look for similar patterns elsewhere in the codebase — utility directories, shared modules, and files adjacent to the changed ones.
2. **Flag any new function that duplicates existing functionality.** Suggest the existing function to use instead.
3. **Flag any inline logic that could use an existing utility** — hand-rolled string manipulation, manual path handling, custom environment checks, ad-hoc type guards, and similar patterns are common candidates.

### Agent 2: Code Quality Review

Review the same changes for hacky patterns:

1. **Redundant state**: state that duplicates existing state, cached values that could be derived, observers/effects that could be direct calls
2. **Parameter sprawl**: adding new parameters to a function instead of generalizing or restructuring existing ones
3. **Copy-paste with slight variation**: near-duplicate code blocks that should be unified with a shared abstraction
4. **Leaky abstractions**: exposing internal details that should be encapsulated, or breaking existing abstraction boundaries
5. **Stringly-typed code**: using raw strings where constants, enums, or typed wrappers already exist in the codebase
6. **Unnecessary structural nesting**: wrapper types, layers, or modules that add no value — check if inner element properties already provide the needed behaviour
7. **Unnecessary comments**: comments that narrate WHAT the code does (well-named identifiers do that), reference the task/caller, or describe the change — delete them; keep only non-obvious WHY (hidden constraints, subtle invariants, workarounds)

### Agent 3: Efficiency Review

Review the same changes for efficiency:

1. **Unnecessary work**: redundant computations, repeated file reads, duplicate network/API calls, N+1 patterns
2. **Missed concurrency**: independent operations run sequentially when they could run in parallel with `InvokeAgent` or parallel tool calls
3. **Hot-path bloat**: new blocking work added to startup or per-request hot paths
4. **Recurring no-op updates**: state updates inside polling loops or event handlers that fire unconditionally — add change-detection so downstream consumers aren't notified when nothing changed
5. **Unnecessary existence checks**: pre-checking file/resource existence before operating (TOCTOU anti-pattern) — operate directly and handle the error instead
6. **Memory**: unbounded data structures, missing cleanup, leaked resources
7. **Overly broad operations**: reading entire files when only a portion is needed, loading all records when filtering for one

## Phase 3: Fix Issues

Wait for all three agents to complete. Aggregate their findings and fix each issue directly in the code. If a finding is a false positive or not worth addressing, note it and move on — do not argue with it, just skip it.

When done, briefly summarise what was fixed (or confirm the code was already clean).
