code-simplify

name	code-simplify
description	Review changed code for YAGNI, removable over-complexity, reuse, code quality, and efficiency, then apply worthwhile simplifications. Use when the user asks to simplify, clean up, tighten, de-hack recent changes, identify logic that can be dropped, or review whether added safeguards and edge-case handling are actually needed.

Code Simplify

Review recent code changes with four lenses: YAGNI, reuse, quality, and efficiency. Fix concrete issues directly while preserving behavior exactly. Prefer readable, explicit code over overly compact cleverness, and avoid churn for style-only tweaks or speculative refactors. Always identify possible parts that can be dropped because they are too complicated for the actual goal or protect against overly specific edge cases.

Workflow

1. Determine the review scope.
   • If the user named a file, directory, function, or time window, use that scope and do not widen it.
   • Otherwise, in a git repository, prefer the current branch diff against the Git Town parent branch:

CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
BASE_BRANCH=$(git-town config get-parent "$CURRENT_BRANCH" 2>/dev/null || true)

• If Git Town cannot resolve a parent, fall back to the branch upstream. If no base or upstream can be resolved, fall back to git diff HEAD.
• If there is no git delta, inspect the files the user mentioned or the files edited earlier in the conversation.
• If no non-empty scope is available, stop and ask what to simplify.

2. Build full context before judging the code.
   • Read the changed files.
   • Search nearby modules and shared utilities for existing helpers before keeping new logic.
   • Check the surrounding patterns so the cleanup matches the codebase instead of imposing a new style.
3. Run the four review passes.
   • If delegation is available and explicitly authorized, run the passes in parallel.
   • Otherwise run them locally, one pass at a time, against the same scope.
   • Keep a short candidate list of logic that may be removable, including checks, branches, fallbacks, normalization, special cases, options, wrappers, abstractions, and compatibility paths.
4. Apply the worthwhile fixes.
   • Change the code directly.
   • Skip false positives or low-value churn without arguing with them.
   • Drop removable complexity directly when evidence shows it is outside the goal, unreachable, redundant, or not worth the maintenance cost.
   • If a drop candidate might change intended behavior or requires a product/API decision, do not remove it silently; report it as a possible drop with the decision needed.
5. Verify the result.
   • Run typecheck and lint when configured and reasonably scoped.
   • Run tests scoped to changed paths when possible.
   • Broaden checks when simplification touched shared utilities, heavily imported modules, data flow, or behavior-sensitive code.
   • If no scoped test mechanism exists and the change has meaningful blast radius, run the full relevant suite.
   • Do not weaken tests, assertions, or types to make verification pass. Fix the simplification or revert the specific simplification that caused the regression.
   • Report what changed and any remaining risks.

Review Passes

YAGNI

• Challenge every new check, guard, fallback, abstraction, option, branch, and normalization step that was added by the current change.
• Keep it only if it is required by the user's stated goal, the current slice contract, existing product behavior, a real caller, a testable failure mode, or a repo convention that already applies here.
• Remove speculative safeguards for edge cases that are not reachable in the current flow, not part of the accepted scope, or not backed by evidence from the codebase.
• Identify over-specific edge-case protection, such as branches for impossible input shapes, future-only compatibility, defensive defaults no caller can hit, duplicate validation after a trusted boundary, or fallbacks for states the surrounding code already prevents.
• Identify over-complicated implementation shape, such as configuration knobs with one caller, abstractions around one behavior, multi-step normalization where a narrow input contract would do, or helpers that make the main path harder to understand.
• Tag drop candidates as delete, stdlib, native, yagni, or shrink when reporting them so the action is obvious.
• Classify each serious candidate as drop now, keep, or ask. Drop it now only when the intended behavior is clear and evidence supports the removal.
• Prefer the smallest implementation that makes the intended behavior work. Do not preserve complexity just because it seems generally defensive.
• If a safeguard is security-, data-loss-, permissions-, migration-, or compatibility-related, verify the concrete risk before removing it. Escalate if the risk is plausible but the requirement is unclear.
• When removing YAGNI code, keep the deletion behavior-preserving for the intended path and note any deliberately unsupported edge case in the final response.

Reuse

• Replace newly written helpers with existing utilities when the behavior already exists.
• Collapse hand-rolled string, path, env, parsing, or type-guard logic into established helpers.
• Remove duplicated functionality introduced under a new name.
• Prefer structural search or project tooling over plain text grep when proving something is unused.

Quality

• Remove redundant state, cached values, or effects when the value can be derived or invoked directly.
• Shrink parameter sprawl by restructuring instead of threading more flags through old APIs.
• Merge copy-paste variants into a shared abstraction when the abstraction stays clearer than the duplication.
• Tighten leaky abstractions and stringly-typed code when existing constants, unions, or boundaries already exist.
• Flatten nested conditionals, ternary chains, and deeply nested switches when guard clauses, early returns, lookup tables, or simple else if chains make the flow easier to verify.
• Remove dead code, unused imports, unused exports, and unreachable branches when project tooling or a reliable search proves they are unused. Account for re-exports, dynamic imports, framework conventions, and public API surfaces; skip uncertain removals.
• Remove unnecessary wrapper elements in component-tree UI frameworks when the wrapper adds no layout, semantic, accessibility, or styling value and the child component can express the needed behavior directly.
• Delete comments that explain what the code does; keep only non-obvious why.

Efficiency

• Remove redundant work, duplicate reads, duplicate requests, and avoidable recomputation.
• Parallelize independent work when the surrounding code supports it cleanly.
• Trim new hot-path work in render, request, startup, polling, or event-heavy paths.
• Add change-detection guards for recurring updates so no-op cycles do not notify downstream consumers.
• Verify wrapper updater/reducer helpers preserve the project's no-change signal, such as same-reference returns, so callers' no-op guards actually work.
• Prefer doing the operation and handling failure over pre-checking existence when that removes a TOCTOU pattern.
• Remove unbounded data structures, missing cleanup, listener leaks, and avoidable retained state introduced by the change.
• Reduce overly broad reads or loads when only a narrow slice is needed.

Guardrails

• Prefer simplification over cleverness.
• Do not invent abstractions just to satisfy the review pass.
• Do not rewrite unrelated code.
• Preserve the existing architecture unless the current change clearly violates it.
• Do not remove docs, plans, rolling-wave artifacts, or other workflow/source-of-truth files just because they are not runtime code.
• Treat public exports and framework entrypoints conservatively; unused-looking code can be externally consumed.
• Escalate instead of forcing a risky refactor that would change behavior, broaden scope, or require a product decision.

Output

• Summarize what was already good, what was simplified, what was dropped as YAGNI, and which checks ran.
• Include a short Possible drops section when there are plausible removals that were not made because they need user/product/API confirmation. Use tags: delete, stdlib, native, yagni, shrink.
• Omit Possible drops when there are no meaningful candidates.
• If the code was already clean enough, say so plainly.
• If checks were not run or could not run, say that explicitly.