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Agent skill

API Design Reviewer

by oxbshw in oxbshw/LLM-Agents-Ecosystem-Handbook

A skill your agent uses when reviewing a proposed REST or GraphQL API change before merge — checks contract clarity, backwards compatibility, errors, pagination, auth, and naming.

MITAuto-check passedBackend & APIs

Install API Design Reviewer

skills CLI
$ npx skills add oxbshw/LLM-Agents-Ecosystem-Handbook --skill api-design-reviewer -a claude-code

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

GitHub CLI
$ gh skill install oxbshw/LLM-Agents-Ecosystem-Handbook api-design-reviewer --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/oxbshw/LLM-Agents-Ecosystem-Handbook.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/catalog/api-design-reviewer .claude/skills/api-design-reviewer && 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
api-design-reviewer
GitHub stars
552
Token cost
~553 tokens
SKILL.md length
239 words
Files
2 (incl. references)
Skills in repo
6
Repo updated
First seen
Licence
MIT

At a glance

A skill your agent uses when reviewing a proposed REST or GraphQL API change before merge — checks contract clarity, backwards compatibility, errors, pagination, auth, and naming.

  • Works in 5 steps: Parse the spec; list the operations /… → For each operation, walk… → For breaking changes, surface the… → …
  • Reviewing a proposed REST
  • SKILL.md covers When to use, When NOT to use, Inputs and Outputs, plus 5 more sections
  • Instructions only: no scripts, shell commands, URLs or credentials in SKILL.md

What it does

API Design Reviewer is an agent skill from oxbshw/LLM-Agents-Ecosystem-Handbook. Use when reviewing a proposed REST or GraphQL API change before merge — checks contract clarity, backwards compatibility, errors, pagination, auth, and naming.

Its SKILL.md is about 550 tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/api-review-checklist.md`).

It sits in Backend & APIs, covering API design and GraphQL. It works with GraphQL. The repository describes itself as: One-stop handbook for building, deploying, and understanding LLM agents with 60+ skeletons, tutorials, ecosystem guides, and evaluation tools. The licence is MIT.

When your agent uses it

  • Reviewing a proposed REST
  • GraphQL API change before merge — checks contract clarity
  • Backwards compatibility

Example prompts

  • “/api-design-reviewer”

Workflow steps

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

  1. Parse the spec; list the operations / types touched
  2. For each operation, walk references/api-review-checklist.md
  3. For breaking changes, surface the contract delta explicitly
  4. Group findings into Critical (blockers), Important (should fix), Nits (style)
  5. Append Open questions for the author

What it can do on your machine

Read from SKILL.md and the folder at commit 7f8ee3c. 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

API Design Reviewer loads about 553 tokens when it runs, and up to ~893 if it reads all its reference files. Until then it costs about 45 tokens; SKILL.md has 239 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it
~45
When it runs · the whole SKILL.md, loaded when a task matches
~553
With references · SKILL.md plus every file in references/, read only if the agent opens them
~893

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

The full file from oxbshw/LLM-Agents-Ecosystem-Handbook at commit 7f8ee3c, republished under its MIT licence (© oxbshw). 239 words, ~553 tokens.

Download SKILL.mdSave it as .claude/skills/api-design-reviewer/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.
name
api-design-reviewer
description
Use when reviewing a proposed REST or GraphQL API change before merge — checks contract clarity, backwards compatibility, errors, pagination, auth, and naming.
version
0.1.0
status
experimental
risk
low
tags
engineering, read-only, writes-files

API Design Reviewer

When to use

  • A new endpoint / mutation / schema is being proposed
  • A breaking change is on the table
  • An API draft needs a second pair of eyes before stakeholder review

When NOT to use

  • Pure implementation details (use repo-auditor)
  • UI / UX feedback
  • Cost / SLA tradeoffs (those need product discussion)

Inputs

NameTypeRequiredNotes
specpath or textyesOpenAPI / GraphQL SDL / Markdown design doc
mode"public" | "internal"noDefault internal. public raises the bar on backwards-compat.

Outputs

A Markdown review with sections: Critical, Important, Nits, Open questions.

Workflow

  1. Parse the spec; list the operations / types touched
  2. For each operation, walk references/api-review-checklist.md:
    • Naming consistent with neighbors?
    • Resource model coherent?
    • Errors enumerated and typed?
    • Pagination present (where lists are returned)?
    • Auth + authz documented?
    • Idempotency on writes?
    • Versioning strategy?
  3. For breaking changes, surface the contract delta explicitly
  4. Group findings into Critical (blockers), Important (should fix), Nits (style)
  5. Append Open questions for the author

References

Success criteria

  • 0 fabricated findings (every finding cites a section of the spec)
  • Critical/Important findings have a concrete suggested fix
  • Tone is collegial, not pedantic

Failure modes

  • Spec too large (> 200 ops) → split into modules and ask the author which to focus on
  • Internal jargon in the spec without definitions → list as Open questions, don't guess

Examples

  • Good: "Critical — GET /users returns an unbounded list. Add cursor pagination (suggested: ?cursor=...&limit=...)."
  • Bad: "I think pagination might be useful here."

© oxbshw, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (references) in skills/catalog/api-design-reviewer of oxbshw/LLM-Agents-Ecosystem-Handbook.

  • SKILL.md
  • references/api-review-checklist.md

Open the folder on GitHubat commit 7f8ee3c

Compare with similar skills

API Design Reviewer 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.

API Design Reviewer compared with similar skills
SkillStarsUsed inTokensAuto-checkLicenceRepo updated
API Design Reviewer this skilloxbshw/LLM-Agents-Ecosystem-Handbook552—~553Automated safety check: PassMIT
Nodejs Backend Patternsever-works/ever-works16218 repos~4kAutomated safety check: PassAGPL-3.0
API DesignerJeffallan/claude-skills12k1 repos~2kAutomated safety check: PassMIT
API Design Principlesjh941213/my-cc-harness12618 repos~3.4kAutomated safety check: PassNone
API And Interface Designdzhalaevd/Donatello1358 repos~2.6kAutomated safety check: PassApache-2.0
Designing APIsCloudAI-X/claude-workflow-v21.4k1 repos~1.2kAutomated safety check: PassMIT

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Works with

Categories

Questions about API Design Reviewer

What does API Design Reviewer do?

A skill your agent uses when reviewing a proposed REST or GraphQL API change before merge — checks contract clarity, backwards compatibility, errors, pagination, auth, and naming. API Design Reviewer is an agent skill from oxbshw/LLM-Agents-Ecosystem-Handbook. Use when reviewing a proposed REST or GraphQL API change before merge — checks contract clarity, backwards compatibility, errors, pagination, auth, and naming.

When should I use API Design Reviewer?

API Design Reviewer fits situations like: reviewing a proposed REST; graphQL API change before merge — checks contract clarity; backwards compatibility.

How do I install API Design Reviewer in Claude Code?

Run `npx skills add oxbshw/LLM-Agents-Ecosystem-Handbook --skill api-design-reviewer -a claude-code`. Or copy the skill folder (skills/catalog/api-design-reviewer in oxbshw/LLM-Agents-Ecosystem-Handbook) into .claude/skills/api-design-reviewer in your project. Claude Code loads it when a task matches its description.

How do I install API Design Reviewer in Codex?

Run `npx skills add oxbshw/LLM-Agents-Ecosystem-Handbook --skill api-design-reviewer -a codex`. Or copy the skill folder (skills/catalog/api-design-reviewer in oxbshw/LLM-Agents-Ecosystem-Handbook) into .agents/skills/api-design-reviewer in your project. Codex loads it when a task matches its description.

Can I use API Design Reviewer 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 oxbshw/LLM-Agents-Ecosystem-Handbook --skill api-design-reviewer -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/api-design-reviewer, .gemini/skills/api-design-reviewer, .github/skills/api-design-reviewer and .opencode/skills/api-design-reviewer in your project.

What does API Design Reviewer need to run?

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

Does API Design Reviewer 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 API Design Reviewer 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 API Design Reviewer use?

API Design Reviewer is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.

How many tokens does API Design Reviewer use?

About 553 tokens (SKILL.md is roughly 2.2k 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 340 tokens, read only when the agent opens those files.

What are the alternatives to API Design Reviewer?

Skills that share tags, products or a category with API Design Reviewer: Nodejs Backend Patterns (ever-works/ever-works, 162 stars), API Designer (Jeffallan/claude-skills, 12k stars), API Design Principles (jh941213/my-cc-harness, 126 stars) and API And Interface Design (dzhalaevd/Donatello, 135 stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.

Who maintains API Design Reviewer?

oxbshw (a GitHub user) maintains it in oxbshw/LLM-Agents-Ecosystem-Handbook, which has 552 GitHub stars. The repository holds 6 skills in this directory. The repository was last updated on June 30, 2026.

Source: oxbshw/LLM-Agents-Ecosystem-Handbook on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.