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.
npx agentmods add skills/cyanheads/toolkit-mcp-server/code-simplifiernpx skills add cyanheads/toolkit-mcp-server --skill code-simplifiergit clone --depth 1 https://github.com/cyanheads/toolkit-mcp-serverWhat 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.
| Model | Per session | Once 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 |
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.
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.
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:
- Read the full files containing changes — not just the diff hunks. Understand imports, surrounding logic, module structure.
- Identify the project language(s) and select the relevant transformation rules. Discard inapplicable rules.
- 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, andnode_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/utilsshould replace raw OTel attribute keys.
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.
- 2d ago First seen · 131 lines · 124 tokens per session scan A b61d1bb9bf8f
code-simplifier is a skill published in the GitHub repository cyanheads/toolkit-mcp-server (18 stars, last pushed 10d 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.
Other skills, from other repositories
build-mcp-server
This skill should be used when the user asks to "build an MCP server", "create an MCP", "make an MCP integration", "wrap an API for Claude", "expose tools to Claude", "make an MCP app", or discusses building something with the Model Context Protocol. It is the entry point for MCP server development — it interrogates…
implementation-strategy
Decide how to implement runtime and API changes before editing code. Use when a task changes exported APIs, MCP tool definitions, runtime behavior, or configuration, and you need to choose the compatibility boundary and implementation shape.
docs-sync
Audit documentation coverage by comparing implementation against docs/. Use when asked to check doc coverage, sync docs with code, or after significant API surface changes. Produce a report and ask for approval before editing.
pr-draft-summary
Generate a PR-ready summary block with branch suggestion, title, and description. Use in the final handoff after moderate-or-larger code changes; skip for trivial or conversation-only tasks.
code-change-verification
Run the verification stack (format, lint, typecheck, test) when changes affect runtime code, tests, or build config.
typescript
This skill should be used when the user asks to "optimize TypeScript performance", "speed up tsc compilation", "configure tsconfig.json", "fix type errors", "improve async patterns", or encounters TS errors (TS2322, TS2339, "is not assignable to"). Also triggers on .ts, .tsx, .d.ts file work involving type…