Skillbooks are Markdown directories served over HTTP — a clean two-type system for packaging and delivering domain expertise. Every skillbook is either a reference or a guide. No proprietary SDK. No platform dependency. No vendor who can pull the rug.
View the Spec on GitHub →The root SKILL.md is a standard skill file any agent can read today, zero integration required. Agents that understand the graph follow links and fetch pages on demand. If you choose to publish through a marketplace or catalog, payment can be layered on top, but that is platform behavior, not part of the standard itself. This is progressive enhancement: it works everywhere, works better when you go deeper.
Any agent can read SKILL.md as a standard skill file. Zero integration effort. It just works.
Graph-aware agents follow links into deeper sections. They navigate the knowledge structure and read only what they need.
Full traversal with citations, rich metadata, and optional marketplace features layered on top. The agent reads deeply, cites every source, and publishers can monetize if they choose.
The entire format is built on things that already exist: Markdown, HTTP, and JSON. No new protocols to learn.
Frontmatter with name, description, and metadata. Table of contents with links to every section. Navigation instructions that tell agents how to traverse the graph.
Machine-readable metadata: title, author, version, page count, type, and optional commercial fields. Everything an agent, tool, or marketplace needs to index and display the skillbook.
Markdown files, 40–100 lines each. One concept per page. Cross-references link related topics. Every claim cites its source.
Relative links between pages. Agents follow the graph like browsing documentation. No routing layer, no query language — just links.
Every skillbook declares a type field: either "reference" or "guide". This is the foundation of the composition model.
What you know. Source material, regulations, encyclopedias, complete works. The authoritative facts an agent needs. Declared as skillbook-type: "reference" in SKILL.md frontmatter and skillbook.type: "reference" in package.json.
What you do. Methodologies, frameworks, checklists, processes. The structured approach to applying knowledge. Declared as skillbook-type: "guide" in SKILL.md frontmatter and skillbook.type: "guide" in package.json.
The power is in pairing them. A reference + guide creates a capability neither has alone. Example: FDA Food Code (reference) + Exam Prep Method (guide) = a food safety study assistant. The type system makes this explicit and discoverable.
Skillbooks are HTTP resources. If your tool can fetch a URL, it can use a skillbook.
The skillbook format is developed in the open. Every improvement starts as a conversation.
Open an issue on GitHub to propose format changes, new metadata fields, or tooling improvements.
Fork the spec repo, make your modifications, and submit a pull request. All contributions are reviewed by maintainers.
Join open issues to discuss direction, trade-offs, and priorities. The best ideas come from real-world usage.
Every book ever written is potential inventory. Every methodology ever documented is a guide waiting to be put to work. Two types compose into infinite capabilities.
The goal is a format that outlives any single platform. Two types + Markdown + HTTP. Marketplace features like payments can sit on top, but the standard stays open and portable. Outdated training is now outdated.