# The Astrid Book

The canonical reference documentation for the Astrid runtime, covering its kernel, capsule model, host ABI, inter-process bus and security model.

The Astrid Book is the canonical reference for Astrid, documenting its kernel, its capsule model, the host ABI, the message bus between components, and its security model. It is built with mdBook and can be served locally for reading.

Its reference appendices, including the capability catalog, host ABI error codes and topic registry, are generated directly from the Astrid source code, and cross-chapter "see also" footers are generated from the same polyrepo checkout, so building the full reference requires the core, wit and capsules repositories checked out as sibling directories.

Website: https://github.com/astrid-runtime/book