code-simplifier

A cleanup review for code changes in the working tree, meaning the files changed but not yet committed to Git.

In plain words
What is it for?
Use it after making significant changes to simplify code, modernize it, and improve how it fits the existing project.
Why use it?
It finds unnecessary complexity, duplication, inefficiencies, and inconsistencies with the surrounding code after a substantial coding session.

Skill for Claude CodeCodex

Part of the attack-surface-mcp-server plugin — 32 skills, 1 MCP server shipped together

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/cyanheads/attack-surface-mcp-server/code-simplifier
Any agent
npx skills add cyanheads/attack-surface-mcp-server --skill code-simplifier
Clone the repo
git clone --depth 1 https://github.com/cyanheads/attack-surface-mcp-server

Made for: Claude Code, Codex.

Or install attack-surface-mcp-server, the plugin that ships this one along with the rest of its 32 skills, 1 MCP server.

Per session 124 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,827 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod 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 $0.00124 $0.02827
Opus 5 $0.00062 $0.01413
Sonnet 5 $0.00025 $0.00565
Haiku 4.5 $0.00012 $0.00283

Measured 2d ago against content hash b61d1bb9bf8f, 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 2d ago.

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.

Origin

This is a copy

100% identical to code-simplifier — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/code-simplifier/SKILL.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Simplifier

Post-session cleanup pass. Reviews what changed, understands how it fits the existing codebase, and makes targeted improvements — modernizing syntax, removing unnecessary complexity, consolidating duplicated logic, catching efficiency issues. Prioritizes codebase cohesion over local perfection.

Core philosophy

Every change must earn its keep. A simplification that doesn't meaningfully improve clarity, correctness, or cohesion is noise. Don't refactor for refactoring's sake. Don't create new files, abstractions, or utilities unless they solve a demonstrated problem. If the existing code works and is readable, leave it alone. The goal is a cohesive codebase, not a pristine one.

Procedure

Phase 1: Identify changes

Run git status to see the shape of the working tree, then git diff HEAD for all uncommitted changes (staged and unstaged). Untracked files never appear in the diff — read new files directly. If the tree is clean, review the most recently modified files from the current session.

Phase 2: Understand the surrounding codebase

Don't review changes in isolation. Before any modifications:

  1. Read the full files containing changes — not just the diff hunks. Understand imports, surrounding logic, module structure.
  2. Identify the project language(s) and select the relevant transformation rules. Discard inapplicable rules.
  3. Survey adjacent code — shared utilities, sibling modules, common patterns. You need to know what already exists before deciding something is missing. For mcp-ts-core projects, check src/utils/ for project utilities, src/errors/ for error handling, and node_modules/@cyanheads/mcp-ts-core/ for framework exports.

Phase 3: Review

Evaluate the changes across these dimensions. Not every dimension applies to every diff — skip what's irrelevant.

Codebase cohesion
  • Reuse — Search for existing utilities, helpers, and patterns that could replace newly-written code. For mcp-ts-core projects, prefer import from '@cyanheads/mcp-ts-core/utils' over hand-rolled equivalents — pagination helpers, schema builders, retry primitives, and OTel attribute constants are framework-provided.
  • Consolidation — Flag copy-paste-with-variation: near-duplicate code blocks that should be unified. Only unify if the shared abstraction is genuinely simpler than the duplicated code.
  • Consistency — Check that new code follows the same patterns as the rest of the codebase: naming conventions, error handling style, import patterns, type annotation style. Normalize toward the better variant when the project is inconsistent.
  • Stringly-typed code — Flag raw strings where constants, string-union types, branded types, or framework attribute constants already exist. For mcp-ts-core projects, the ATTR_* constants in @cyanheads/mcp-ts-core/utils should replace raw OTel attribute keys.

Read the full file on GitHub · 131 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. 2d ago First seen · 131 lines · 124 tokens per session scan A b61d1bb9bf8f

Subscribe to this mod's changes

code-simplifier is a skill published in the GitHub repository cyanheads/attack-surface-mcp-server (1 stars, last pushed 3d ago), licensed Apache-2.0. It adds 124 tokens to every session and 2,827 once invoked, about $0.0006 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to code-simplifier, differing in 0 lines, and is treated as a copy.

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