What is api-design-reviewer?

A review checklist for proposed REST or GraphQL API changes. An API is a defined way for software systems to exchange data; REST and GraphQL are two common ways to design those interfaces.

Review an OpenAPI document, GraphQL schema, or design document for naming, resource structure, errors, pagination, access control, idempotency, and versioning.

It helps catch unclear contracts, breaking changes, incomplete error handling, missing pagination, and undocumented authentication before implementation or merge. It also separates serious issues from smaller style concerns.

api-design-reviewer — Skill for Claude Code and Codex by oxbshw

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.

Any agent

npx skills add oxbshw/LLM-Agents-Ecosystem-Handbook --skill api-design-reviewer

Clone the repo

git clone --depth 1 https://github.com/oxbshw/LLM-Agents-Ecosystem-Handbook

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/oxbshw/llm-agents-ecosystem-handbook/api-design-reviewer/github.svg)](https://agentmods.dev/skills/oxbshw/llm-agents-ecosystem-handbook/api-design-reviewer)

Your own site

<a href="https://agentmods.dev/skills/oxbshw/llm-agents-ecosystem-handbook/api-design-reviewer"><img src="https://agentmods.dev/badge/skills/oxbshw/llm-agents-ecosystem-handbook/api-design-reviewer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/oxbshw/llm-agents-ecosystem-handbook/api-design-reviewer"><img src="https://agentmods.dev/badge/skills/oxbshw/llm-agents-ecosystem-handbook/api-design-reviewer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 35 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 530 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits

NVIDIA SkillSpector pass 7 Sept 2026

How audits are shown

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.

Model	Per session	Once invoked
Fable 5.1	$0.00035	$0.00530
Opus 5.5	$0.00014	$0.00212
Sonnet 5.5	$0.00007	$0.00106
Haiku 4.5	$0.00003	$0.00053

Measured 2mo ago against content hash d20421b4c4e1, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

api-design-reviewer 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 2mo 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.

skills/catalog/api-design-reviewer/SKILL.md · 60 lines

What it actually says

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

Name	Type	Required	Notes
`spec`	path or text	yes	OpenAPI / GraphQL SDL / Markdown design doc
`mode`	`"public"` \| `"internal"`	no	Default `internal`. `public` raises the bar on backwards-compat.

Outputs

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

Workflow

Parse the spec; list the operations / types touched
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?
For breaking changes, surface the contract delta explicitly
Group findings into Critical (blockers), Important (should fix), Nits (style)
Append Open questions for the author

References

references/api-review-checklist.md

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."

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

references/api-review-checklist.md 1.3 KB

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.

2mo ago First seen · 60 lines · 35 tokens per session scan A d20421b4c4e1

Subscribe to this mod's changes

api-design-reviewer is a skill published in the GitHub repository oxbshw/LLM-Agents-Ecosystem-Handbook (558 stars, last pushed 4mo ago), licensed MIT. It adds 35 tokens to every session and 530 once invoked, about $0.0001 per session on Opus 5.5. 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.

Backend and APIs Code review ai ai-agent ai-agents engineering fine-tuning finetuning-llms freamework read-only writes-files

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