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Agent skill

Express API Design

by revfactory in revfactory/claude-code-harness

Express.js REST API design and implementation guide. An agent skill from revfactory/claude-code-harness.

No licenceAuto-check passedBackend & APIs

Install Express API Design

skills CLI
$ npx skills add revfactory/claude-code-harness --skill express-api-design -a claude-code

Project install by default; add -g for ~/.claude/skills/.

GitHub CLI
$ gh skill install revfactory/claude-code-harness express-api-design --agent claude-code

Project scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).

Manual copy
$ git clone --depth 1 https://github.com/revfactory/claude-code-harness.git skills-src && mkdir -p .claude/skills && cp -r skills-src/experiments/results/case-001/harness/.claude/skills/express-api-design .claude/skills/express-api-design && rm -rf skills-src

Use ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.

Claude Code skills documentation · loads skills from .claude/skills/

Facts

Skill name
express-api-design
GitHub stars
120
Token cost
~276 tokens
SKILL.md length
100 words
Files
2 (incl. references)
Skills in repo
15
Repo updated
First seen
Licence
None found

At a glance

Express.js REST API design and implementation guide. An agent skill from revfactory/claude-code-harness.

  • Works in 8 steps: 모든 라우트는 controllers를 통해 처리 → 에러는 글로벌 에러 핸들러로 전파 (컨트롤러에서 throw) → 입력 유효성 검사는 미들웨어에서 처리하여 재사용 → …
  • Implementing REST API endpoints
  • SKILL.md covers 프로젝트 구조, REST 규칙 and 핵심 원칙
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

Express API Design is an agent skill from revfactory/claude-code-harness. Express.js REST API design and implementation guide. Use when implementing REST API endpoints, creating Express routes, or setting up API project structure with MVC pattern.

Its SKILL.md is about 280 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/patterns.md`).

It sits in Backend & APIs, covering API design and REST APIs. It works with Express.

When your agent uses it

  • Implementing REST API endpoints
  • Creating Express routes
  • Setting up API project structure with MVC pattern

Example prompts

  • “/express-api-design”

Workflow steps

8 steps, taken from the first numbered list in SKILL.md.

  1. 모든 라우트는 controllers를 통해 처리
  2. 에러는 글로벌 에러 핸들러로 전파 (컨트롤러에서 throw)
  3. 입력 유효성 검사는 미들웨어에서 처리하여 재사용
  4. 일관된 에러 응답 형식: { error: "메시지" }
  5. JSON 파싱 에러 별도 처리
  6. 데이터 모델은 클래스 기반 싱글턴 스토어로 구현
  7. 반환 시 스프레드 복사본 사용하여 불변성 보장
  8. 자동 ID 생성 (auto-increment) 및 createdAt 자동 설정

What it can do on your machine

Read from SKILL.md and the folder at commit 267005c. It shows what the files ask for, not the result of running them.

  • Tool permissions

    Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

    From allowed-tools in the SKILL.md frontmatter.

  • Runs code

    No scripts in the folder and no shell commands in SKILL.md.

    From the folder's file list and the shell code blocks in SKILL.md.

  • Network

    No URLs in SKILL.md.

    From URLs in SKILL.md, links to its own repository left out.

  • Credentials

    Names no API keys, tokens, secrets or passwords.

    From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Express API Design loads about 276 tokens when it runs, and up to ~825 if it reads all its reference files. Until then it costs about 48 tokens; SKILL.md has 100 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~48
When it runs · the whole SKILL.md, loaded when a task matches
~276
With references · SKILL.md plus every file in references/, read only if the agent opens them
~825

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Auto-check passed

The automated check found no risky patterns in SKILL.md.

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

Without a licence we can't republish the file, so here is its outline and opening line. It has 100 words (~276 tokens).

name
express-api-design

Read the full SKILL.md on GitHub

Files

SKILL.md and 1 other file (references) in experiments/results/case-001/harness/.claude/skills/express-api-design of revfactory/claude-code-harness.

  • SKILL.md
  • references/patterns.md

Open the folder on GitHubat commit 267005c

Compare with similar skills

Express API Design next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.

Express API Design compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
Express API Design this skillrevfactory/claude-code-harness120—~276Automated safety check: PassNone
API DesignerJeffallan/claude-skills12k2 repos~2kAutomated safety check: PassMIT
Nodejs Backend Patternsever-works/ever-works15817 repos~4kAutomated safety check: PassAGPL-3.0
Pangolin CRUD Endpointsfosrl/pangolin23k—~461Automated safety check: PassCustom licence
Old Coder API DesignAmazingAng/old-coder7491 repos~3.4kAutomated safety check: PassMIT
REST API Contract Reviewdecebals/claude-code-java7501 repos~2.8kAutomated safety check: PassMIT

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    Build production-ready Node.js backend services with Express/Fastify, implementing middleware patterns, error handling, authentication, database integration, and API design best practices.

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    749 GitHub starsUsed in 1 repo~3.4k tokens
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Works with

Categories

Questions about Express API Design

What does Express API Design do?

Express.js REST API design and implementation guide. An agent skill from revfactory/claude-code-harness. Express API Design is an agent skill from revfactory/claude-code-harness.js REST API design and implementation guide.

When should I use Express API Design?

Express API Design fits situations like: implementing REST API endpoints; creating Express routes; setting up API project structure with MVC pattern.

How do I install Express API Design in Claude Code?

Run `npx skills add revfactory/claude-code-harness --skill express-api-design -a claude-code`. Or copy the skill folder (experiments/results/case-001/harness/.claude/skills/express-api-design in revfactory/claude-code-harness) into .claude/skills/express-api-design in your project. Claude Code loads it when a task matches its description.

How do I install Express API Design in Codex?

Run `npx skills add revfactory/claude-code-harness --skill express-api-design -a codex`. Or copy the skill folder (experiments/results/case-001/harness/.claude/skills/express-api-design in revfactory/claude-code-harness) into .agents/skills/express-api-design in your project. Codex loads it when a task matches its description.

Can I use Express API Design in Cursor, Gemini CLI or GitHub Copilot?

Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add revfactory/claude-code-harness --skill express-api-design -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/express-api-design, .gemini/skills/express-api-design, .github/skills/express-api-design and .opencode/skills/express-api-design in your project.

What does Express API Design need to run?

SKILL.md names no scripts, command-line tools or credentials: Express API Design is instructions for the agent only.

Does Express API Design access the network?

SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.

Is Express API Design safe to install?

Our automated static check of SKILL.md found no risky patterns, such as piping downloads into a shell, reading credential files or hidden Unicode. It is not a guarantee. Review the folder before installing.

What licence does Express API Design use?

No licence was found for Express API Design or its repository. Without one, default copyright applies: ask the author before reusing or redistributing it.

How many tokens does Express API Design use?

About 276 tokens (SKILL.md is roughly 1.1k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 549 tokens, read only when the agent opens those files.

What are the alternatives to Express API Design?

Skills that share tags, products or a category with Express API Design: API Designer (Jeffallan/claude-skills, 12k stars), Nodejs Backend Patterns (ever-works/ever-works, 158 stars), Pangolin CRUD Endpoints (fosrl/pangolin, 23k stars) and Old Coder API Design (AmazingAng/old-coder, 749 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains Express API Design?

revfactory (a GitHub user) maintains it in revfactory/claude-code-harness, which has 120 GitHub stars. The repository holds 15 skills in this directory. The repository was last updated on March 6, 2026.

Source: revfactory/claude-code-harness on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.