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api-endpoint SKILL.md skillA

This file is byte-identical to the first copy the registry indexed, one of 9 indexed copies. Same content hash, so the same checks give both the same grade.

api-endpoint from globalmpc/backendskills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.

Install it, pinned

mdr add globalmpc/backendskills/api-endpoint@git:20261105.6131a31

Pins git:20261105.6131a31 in mdr.lock. Pin the fingerprint instead.

Audit grade: A, 17 of 17 checks passed
Kind: SKILL.md skill
Repository: globalmpc/backendskills
Path: bench/results/2026-11-04/checkout-with-1-20261104173809-28998/skills/api-endpoint/SKILL.md
Versions recorded: 1
Latest version: git:20261105.6131a31, committed Nov 5, 2026
Size: 3,823 bytes
Repository stars: 25
License: MIT

Rules for HTTP API endpoints. Use when adding or changing any endpoint (route, request or response shape, status codes), especially login and ones that read or change other users' data.

Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.

What the file says

# API endpoint

Examples are TypeScript with `pg`. The rules apply to any stack.

Anything that changes money, stock or balances, or calls a payment provider or email: also follow the
`data-integrity` skill (transactions, locks, idempotency).

## 1. Check who may call it, not just that they're logged in

Why: a logged-in user who changes the id in the URL reads or edits someone else's data (IDOR).

```ts
// Bad: any logged-in user can read any invoice
const { rows } = await pool.query("select * from invoices where id = $1", [id]);

// Good: scope the query to the caller; someone else's invoice looks the same as a missing one
const { rows } = await pool.query("select * from invoices where id = $1 and account_id = $2", [id, user.accountId]);
if (rows.length === 0) return sendError(res, 404, "not_found", "Invoice not found");
```

Admins or other roles get access through an explicit role check, never by skipping the filter.

## 2. Bad input is a 4xx, never a 500

Why: a 500 on bad input hides real errors in the noise. Bad values that slip through (negative amounts,
fractions) corrupt data.
…

Read the whole file at its exact version.

How to install

The exact contents, by fingerprint

mdr add globalmpc/backendskills/api-endpoint@sha256:c6cbb040af6956de

The line at the top of this page pins the label git:20261105.6131a31, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.

Badge

[![mdr](https://markdownregistry.com/badge/art_4xzd7kxper5ma2uq.svg)](https://markdownregistry.com/a/art_4xzd7kxper5ma2uq)

4 badge image fetches in 30 days. What the badge shows.

Versions

The registry has recorded 1 version of this file, committed on Nov 5, 2026.

version	committed	commit	size	audit
git:20261105.6131a31 latest	2026-11-05	6131a31	3,823 B	A	view

Audit of the latest version

A 17 of 17 checks passed. Fixed automatic checks with no AI involved, so the same checks give the same answer every run.

pass: Frontmatter block present
pass: Frontmatter declares a name
pass: Frontmatter declares a description
pass: Size between 200 bytes and 200 KB (3823 bytes)
pass: No zero-width or bidi control characters
pass: No instruction hidden inside an HTML comment
pass: No link to an exfiltration or paste host
pass: No credential-shaped string
pass: No instruction to send local credentials anywhere
pass: No text hidden with inline styles
pass: No prompt-injection phrasing
pass: No curl or wget piped into a shell
pass: No recursive delete of root, home or parent
pass: No instruction to read or print local credentials
pass: No base64 blob over 200 characters
pass: No link to a raw IP address
pass: No script tag

Source

GitHub

globalmpc/backendskills · 25 stars · license MIT · pushed 2026-11-06 · branch main

API

GET https://markdownregistry.com/api/v1/artifacts/art_4xzd7kxper5ma2uq
GET https://markdownregistry.com/api/v1/resolve?ref=globalmpc/backendskills/api-endpoint
GET https://markdownregistry.com/api/v1/blob/c6cbb040af6956def1a6fc7e319305fb8bd7aab2f2ed3f03a0f4ce2e2bcc1a56

Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.

Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.

More from globalmpc/backendskills

api-endpoint SKILL.md skill

globalmpc/backendskills · bench/results/2026-11-04/checkout-with-1-20261104164959-6498/skills/api-endpoint/SKILL.md · Rules for HTTP API endpoints. Use when adding or changing any endpoint (route, request or response shape, status…