What is api-design-guidelines?

A review guide for Go HTTP APIs, which are web services that receive and return requests over the internet.

Use it when building or reviewing Go web services, REST APIs, HTTP handlers, or middleware, which is code that runs around request handlers.

It helps find problems in routing, request checks, authentication, security, speed, logging, and the order of shared request-handling code.

api-design-guidelines — Skill for Claude Code and Codex by daibang123a

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 daibang123a/golang-agent-skills --skill api-design-guidelines

Clone the repo

git clone --depth 1 https://github.com/daibang123a/golang-agent-skills

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/daibang123a/golang-agent-skills/api-design-guidelines/github.svg)](https://agentmods.dev/skills/daibang123a/golang-agent-skills/api-design-guidelines)

Your own site

<a href="https://agentmods.dev/skills/daibang123a/golang-agent-skills/api-design-guidelines"><img src="https://agentmods.dev/badge/skills/daibang123a/golang-agent-skills/api-design-guidelines/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/daibang123a/golang-agent-skills/api-design-guidelines"><img src="https://agentmods.dev/badge/skills/daibang123a/golang-agent-skills/api-design-guidelines.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 2,280 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.

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	$0.00080	$0.02280
Opus 5.5	$0.00032	$0.00912
Sonnet 5.5	$0.00016	$0.00456
Haiku 4.5	$0.00008	$0.00228

Measured 2mo ago against content hash aed2a653d347, 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-guidelines 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.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/api-audit.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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/api-design-guidelines/SKILL.md · 197 lines

How it starts

The opening of the file, as written. The whole thing — 197 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Go API Design Guidelines

Review and build Go HTTP APIs following REST best practices, security hardening, and production-grade patterns. 80+ rules across 9 categories.

How It Works

Agent examines HTTP handler code, middleware, routing, and configuration
Agent applies rules by category in priority order
Agent suggests specific fixes with idiomatic Go code examples
Agent references supporting docs for deep-dive topics

Rules

1. Routing & Middleware (Critical)

#	Rule	Description
R1	Use Go 1.22+ ServeMux or a minimal router	`http.ServeMux` now supports `GET /users/{id}`. Prefer stdlib for simple APIs. Use `chi` or `gorilla/mux` only when pattern matching is insufficient.
R2	Apply middleware in correct order	Order matters: Recovery → Logging → CORS → Auth → Rate Limit → Handler.
R3	Use middleware for cross-cutting concerns	Authentication, logging, tracing, rate limiting, and CORS belong in middleware, not in handlers.
R4	Group routes by resource	`/api/v1/users`, `/api/v1/users/{id}`, `/api/v1/users/{id}/orders`.
R5	Use http.Handler interface	All middleware should accept and return `http.Handler` for composability.
R6	Set timeouts on http.Server	Always set `ReadTimeout`, `WriteTimeout`, `IdleTimeout`. Never use `http.ListenAndServe` with default server.

// GOOD: Production server with timeouts
srv := &http.Server{
    Addr:         ":8080",
    Handler:      mux,
    ReadTimeout:  5 * time.Second,
    WriteTimeout: 10 * time.Second,
    IdleTimeout:  120 * time.Second,
}

2. Request Handling (Critical)

#	Rule	Description
Q1	Validate all input	Never trust client input. Validate struct fields, query params, path params.
Q2	Limit request body size	Use `http.MaxBytesReader` to prevent memory exhaustion from large payloads.
Q3	Use json.Decoder, not io.ReadAll + json.Unmarshal	Decoder streams and can enforce `DisallowUnknownFields()`.
Q4	Return early on validation errors	Don't process a request if input is invalid. Return 400 immediately.
Q5	Bind path params safely	Always validate and convert path parameters. Never use raw strings in queries.

Read the full file on GitHub · 197 lines

Files

What ships with it

3 files 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.

2mo ago First seen · 197 lines · 80 tokens per session scan A aed2a653d347

Subscribe to this mod's changes

api-design-guidelines is a skill published in the GitHub repository daibang123a/golang-agent-skills (2 stars, last pushed 8mo ago), licensed MIT. It adds 80 tokens to every session and 2,280 once invoked, about $0.0003 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 2026-08-31.

Backend and APIs Code review

api-design-guidelines next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
api-design-guidelinesdaibang123a/golang-agent-skills	Skill	2	8mo ago	MIT	A	80	Claude Code, Codex
platform-apex-generateforcedotcom/sf-skills	Skill	1.1k	2d ago	Apache-2.0	A	122	Claude Code
flow-next-impl-reviewgmickel/flow-next	Skill	717	yesterday	MIT	A	34	Claude Code, Codex
api-contract-reviewTencentCloudBase/CloudBase-AI-Toolkit	Skill	1.2k	yesterday	MIT	A	54	Claude Code
ring:migrating-to-lib-observabilityLerianStudio/ring	Skill	218	6d ago	Apache-2.0	A	104	Cursor
flow-next-resolve-prgmickel/flow-next	Skill	717	yesterday	MIT	A	36	Claude Code, Codex
ring:mapping-streaming-eventsLerianStudio/ring	Skill	218	6d ago	Apache-2.0	A	95	Cursor