code-simplifier

A code-review helper that simplifies recently changed code while keeping its observable behavior the same. It looks for unnecessary complexity, repetition, deep nesting, and abstractions that do not help.

In plain words
What is it for?
Use it after implementing features, refactoring code, or adding complex logic to identify clearer control flow and focused helper functions.
Why use it?
It removes cleanup work after adding or changing logic and helps keep code readable without changing what the program does. It skips changes where simplification is unlikely to help, such as documentation-only edits.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/csabakovacs/rulesmith/code-simplifier
Any agent
npx skills add CsabaKovacs/rulesmith --skill code-simplifier
Clone the repo
git clone --depth 1 https://github.com/CsabaKovacs/rulesmith

Made for: Claude Code, Codex.

Per session 28 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 614 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00028 $0.00614
Opus 5 $0.00014 $0.00307
Sonnet 5 $0.00006 $0.00123
Haiku 4.5 $0.00003 $0.00061

Measured yesterday against content hash 0c6dbc5ee650, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

code-simplifier scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agents/skills/code-simplifier/SKILL.md · 66 lines

How it starts

The opening of the file, as written. The whole thing — 66 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Simplifier

Simplifies recently changed code for clarity and maintainability while preserving external behavior.

When to Activate

  • After code modifications that introduce new logic, refactor existing code, or add significant complexity.
  • Skip for trivial changes, deletions-only, config changes, or documentation edits.

Simplification Methodology

Follow these steps in order:

  • Identify recently changed functions, classes, and modules.
  • Look for unnecessarily verbose control flow that can be simplified.
  • Find repeated patterns that can be consolidated (only when 3+ concrete occurrences exist).
  • Check for over-abstraction: remove indirection layers that do not add value.
  • Check for under-abstraction: consolidate duplicated logic into focused helpers when repetition is proven.
  • Simplify deeply nested code by extracting guard clauses and early returns.
  • Verify that every proposed simplification preserves identical external behavior.
  • Prefer clarity over cleverness — readable code beats short code.
  • Do NOT rename broadly; only rename within the touched scope when it meaningfully improves readability.
  • Apply changes directly — this agent modifies code, unlike review-only agents.

Stack-Specific Simplification Rules

  • Replace verbose promise chains with async/await where it improves readability. (evidence: packages/core/src/scanner/index.ts)
  • Consolidate repeated type assertions into a single type guard function. (evidence: packages/core/src/render/rulebook.ts)
  • Prefer Array.method() chains over manual for-loops when intent is clearer. (evidence: packages/core/src/scanner/index.ts)
  • Flatten deeply nested if/switch in AST visitors into early-return guard clauses. (evidence: packages/core/src/render/ast.ts)

Project Conventions to Preserve

  • Module-level functions, no class wrappers. Record<string, unknown> for JSON, never any.
  • Constants: UPPER_SNAKE_CASE. Functions: camelCase. Types: PascalCase.
  • .js extensions in imports. File I/O through safe.ts only.
  • Private helpers are unexported module-scoped functions.

Read the full file on GitHub · 66 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 66 lines · 28 tokens per session scan A 0c6dbc5ee650

Subscribe to this mod's changes

code-simplifier is a skill published in the GitHub repository CsabaKovacs/rulesmith (15 stars, last pushed 4mo ago), licensed Apache-2.0. It adds 28 tokens to every session and 614 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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