Developer resources - agentmarkup packages, API, and machine-readable files

agentmarkup developer resources: npm packages for Vite, Astro, Next.js and Nuxt, the OpenAPI 3.1 spec for the public checker and security-scan endpoints, llms.txt, markdown mirrors, and the agent skill.

agentmarkup developer resources

Everything needed to build with agentmarkup, in one place: the packages, the machine-readable files this site publishes about itself, the API behind the public tools, and the agent integrations. There are no API keys and no accounts, because nothing here needs one.

Install a package

agentmarkup is a build-time dependency. Pick the adapter that owns your final build output:

• @agentmarkup/vite, @agentmarkup/astro, @agentmarkup/next and @agentmarkup/nuxt are the framework adapters.
• @agentmarkup/cli runs the same pipeline over any built static output and gates a CI job with agentmarkup check ./dist.
• @agentmarkup/audit fetches a live URL as each major AI crawler and diffs against a browser: npx @agentmarkup/audit https://example.com.
• @agentmarkup/core exposes the generators and validators for custom prerender pipelines.

Setup guides live in the Learning Center: llms.txt, JSON-LD, AI crawlers and auditing a live site.

API reference

The website checker and the security scan are backed by two read-only HTTP endpoints. They are described by an OpenAPI 3.1 document at /openapi.json, with a unique operation ID, typed parameters and response schemas for every operation.

• GET or POST /api/v1/check - fetch a public site's homepage, llms.txt, robots.txt, sitemap and markdown mirrors, and return the raw resources.
• POST /api/v1/security-scan - passive checks over publicly observable headers and DNS records.

The stable contract is versioned in the path. The unversioned /api/check and /api/security-scan are permanent aliases for v1 and will keep working, but integrate against the versioned form. A breaking change would ship as /api/v2/ rather than changing v1, and a version scheduled for removal would carry Deprecation and Sunset headers with at least 180 days notice. Nothing is deprecated today.

Every response carries the IETF RateLimit-Policy, RateLimit-Limit, RateLimit-Remaining and RateLimit-Reset header fields, and a 429 adds Retry-After. Read them and self-throttle rather than discovering the limit by being refused. Everything under /api/ answers JSON, including errors for paths that do not exist.

No key is required. Both are rate-limited per client IP and may ask for a Cloudflare Turnstile token after repeated requests, and every error response carries a stable machine-readable code alongside a human-readable error. Point them only at sites you own or are authorized to test; the Terms of Service set out the limits and the Privacy Policy covers what is stored.

These endpoints exist to serve the tools on this site. They are documented so that agents use them correctly rather than by guessing, not as a hosted product, and there is no uptime guarantee.

Machine-readable files

This site is built with agentmarkup, so its own machine-readable surface is generated by the packages you would install:

• /llms.txt - the site manifest, including when to use agentmarkup
• /llms-full.txt - the same manifest with page content inlined
• /openapi.json - the API surface above
• /sitemap.xml and /robots.txt - every indexable URL, and the AI crawler directives
• A markdown mirror of every page, at the same path with a .md extension, for example /developers.md. Requesting any page with Accept: text/markdown returns the mirror at the original URL.

Agent integrations

The agentmarkup agent skill teaches a coding agent to install the right package, configure it from what the repository already declares, audit the output, and fix what it finds. It never invents a readiness score and never claims a site blocks AI from a single blocked request.

The same skill ships as a Claude Code plugin from the repository marketplace.

Source and support

The source is MIT licensed. Bugs and feature requests belong in GitHub issues; see Support for where to start and Contact for direct addresses, including security reports.