# 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. Source: https://agentmarkup.dev/developers/ For developers # 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](/learn/): [llms.txt](/docs/llms-txt/), [JSON-LD](/docs/json-ld/), [AI crawlers](/docs/ai-crawlers/) and [auditing a live site](/docs/audit/). ## API reference The [website checker](/checker/) and the [security scan](/security-scan/) are backed by two read-only HTTP endpoints. They are described by an OpenAPI 3.1 document at [`/openapi.json`](/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 authorised to test; the [Terms of Service](/terms/) set out the limits and the [Privacy Policy](/privacy/) 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](/llms.txt) - the site manifest, including when to use agentmarkup - [/llms-full.txt](/llms-full.txt) - the same manifest with page content inlined - [/openapi.json](/openapi.json) - the API surface above - [/sitemap.xml](/sitemap.xml) and [/robots.txt](/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](/developers.md). Requesting any page with `Accept: text/markdown` returns the mirror at the original URL. ## Agent integrations The [agentmarkup agent skill](https://github.com/agentmarkup/agentmarkup/tree/main/skills/agentmarkup) 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](https://github.com/agentmarkup/agentmarkup/tree/main/plugins/agentmarkup). ## Source and support The [source](https://github.com/agentmarkup/agentmarkup) is MIT licensed. Bugs and feature requests belong in [GitHub issues](https://github.com/agentmarkup/agentmarkup/issues); see [Support](/support/) for where to start and [Contact](/contact/) for direct addresses, including security reports.