api-review

A code-review guide for checking an application programming interface (API), the way software exposes operations and data to other software. It uses canonical API design guidelines.

In plain words
What is it for?
Use it to review specified files for contract clarity, simplicity, naming, command/query separation, validation, and explicit dependency configuration.
Why use it?
It helps find unclear interfaces, unnecessary options, surprising names, weak type usage, hidden dependencies, and other design problems before they spread.

Skill for Claude CodeCodex

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/flutter/agent-plugins/api-review
Any agent
npx skills add flutter/agent-plugins --skill api-review
Clone the repo
git clone --depth 1 https://github.com/flutter/agent-plugins

Made for: Claude Code, Codex.

Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 450 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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.

ModelPer sessionOnce invoked
Fable 5 $0.00034 $0.00450
Opus 5 $0.00017 $0.00225
Sonnet 5 $0.00007 $0.00090
Haiku 4.5 $0.00003 $0.00045

Measured yesterday against content hash 75dfef71701f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

api-review 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 yesterday.

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

Copies of this mod

1 near-identical copy found in the catalogue:

.agents/agents/reidbaker-agent/skills/api-review/SKILL.md · 30 lines

What it actually says

API review skill

This skill reviews code against the canonical API Design guidelines.

Instructions

  1. Load Guidelines: Read the API design guidelines from references/canonical_api_design.md to ensure they are fully available in the context.
  2. Identify Target: Identify the code to review.
    • If the user specified files (e.g., "review main.dart"), use those.
    • If the user has an open file in their context, assume that is the target.
    • If neither, ask the user to specify the target files.
  3. Analyze: For each target file, perform a deep analysis against the "Foundations of Canonical API Design Principles" (loaded in step 1), specifically looking for:
    • Contract-First: Is the interface clear and decoupled from implementation?
    • KISS/YAGNI: Are there unnecessary parameters or over-generalized features?
    • Ergonomics: Are names intent-revealing? Do they follow the Principle of Least Astonishment?
    • CQS: Are commands and queries separated?
    • Safety: Are types used strictly (Enums vs Strings)? Is validation visible?
    • Explicit Configuration: Are dependencies explicitly injected rather than implicitly resolved via global state, registries, or environment variables?
  4. Report: Generate a structured report:
    • Score: Give a letter grade (A-F) based on alignment.
    • Critical Issues: Violations that must be fixed (e.g., severe strictness or safety issues).
    • Suggestions: Ergonomic improvements (renaming, rearranging).
    • Code Examples: Provide before vs after code blocks for the suggested improvements.
    • Save the report as a markdown artifact in the conversation artifacts directory (e.g., <appDataDir>/brain/<conversation-id>/api_review_results.md).
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.

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. yesterday First seen · 30 lines · 34 tokens per session scan A 75dfef71701f

Subscribe to this mod's changes

api-review is a skill published in the GitHub repository flutter/agent-plugins (2,895 stars, last pushed 3d ago), licensed BSD-3-Clause. It adds 34 tokens to every session and 450 once invoked, about $0.0002 per session on Opus 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.

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