A guide for generating an OpenAPI 3.1 document from an Express application. OpenAPI is a standard description of an HTTP API, including its routes, inputs, outputs, and security.

Use it to document Express endpoints, their parameters, responses, authentication, request and response data, source locations, and plain-language operation summaries.

It turns route code into usable API documentation and replaces guessed placeholder schemas with details grounded in each handler.

openapi-doc — Skill for Claude Code and Codex by chiz0me: A guide for generating an OpenAPI 3.1 document from…

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/chiz0me/express-recon/openapi-doc

Any agent

npx skills add chiz0me/express-recon --skill openapi-doc

Clone the repo

git clone --depth 1 https://github.com/chiz0me/express-recon

Made for: Claude Code, Codex.

Or install express-recon, the plugin that ships this one along with the rest of its 2 skills, 1 MCP server.

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/chiz0me/express-recon/openapi-doc.svg)](https://agentmods.dev/skills/chiz0me/express-recon/openapi-doc)

Your own site

<a href="https://agentmods.dev/skills/chiz0me/express-recon/openapi-doc"><img src="https://agentmods.dev/badge/skills/chiz0me/express-recon/openapi-doc.svg" alt="Measured on agentmods" height="20"></a>

Per session 123 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 3,304 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.

Model	Per session	Once invoked
Fable 5	$0.00123	$0.03304
Opus 5	$0.00062	$0.01652
Sonnet 5	$0.00025	$0.00661
Haiku 4.5	$0.00012	$0.00330

Measured today against content hash d791965da184, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

openapi-doc 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 today.

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/openapi-doc/SKILL.md · 265 lines

How it starts

The opening of the file, as written. The whole thing — 265 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OpenAPI/Swagger documentation (express-recon)

Turns a supported HTTP codebase into a documented OpenAPI 3.0 or 3.1 document in two layers:

Skeleton (deterministic). express-recon emits OpenAPI 3.1 for a new document, or preserves the dialect of an authored OpenAPI 3.0/3.1 base. It emits paths, methods, path/query/header parameters, response status codes, per-operation security (only from explicit auth-tag/security-scheme mapping), and statically-mined request/response hints and any statically resolved validator/framework schemas — plus an x-express-recon extension per operation carrying the handler source file:line, framework, applicationId, authStatus, middleware chain, handlerResolved, handlerName, and handlerSource.
Enrichment (AI code review — this skill). You inspect the schema evidence, read handlers where evidence remains incomplete or contradictory, refine the unresolved JSON Schema, and write a human summary/description per operation.

The document-level x-express-recon.schemasArePlaceholders: true means some generated surface may remain under-specified. Low/medium-confidence fragments carry x-express-recon-unrefined: true; high-confidence static Fastify, Zod/Joi, express-validator, or NestJS validator/Swagger evidence does not. Your job is to verify that evidence and refine only what remains ungrounded.

0. Locate the tool

Use whichever resolves first (same as the audit skill):

express-recon on PATH, else
node ${CLAUDE_PLUGIN_ROOT}/src/cli.js (installed plugin; if ${CLAUDE_PLUGIN_ROOT}/node_modules is missing, run npm install --omit=dev --prefix ${CLAUDE_PLUGIN_ROOT} once first), else
node <path-to-express-recon>/src/cli.js (a local checkout).

If none is available, tell the user how to install it and stop.

1. Discover and create the refresh workspace

Discover app identities and existing documentation first. Do not merge multiple apps just because they share a repository:

Read the full file on GitHub · 265 lines

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.

today Changed · +79 lines · +1 tokens per session d791965da184
4d ago First seen · 186 lines · 122 tokens per session scan A e87f2d479b02

Subscribe to this mod's changes

openapi-doc is a skill published in the GitHub repository chiz0me/express-recon (0 stars, last pushed 2d ago), licensed MIT. It adds 123 tokens to every session and 3,304 once invoked, about $0.0006 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 2026-08-31.

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