> **Vendored from upstream**, pinned at SHA `7765fae`. One file lives next to this note:
>
> - `galaxy.xsd` — the structured source. **Agents and casting should consume this** when authoring or validating Galaxy tool wrapper XML, tool tests, output assertions, macros, inputs, outputs, help, citations, and configfile blocks. Sync is manual.
>
> **When to consult:** authoring or validating `tool.xml` wrappers, translating tool parameters into Galaxy XML, defining outputs or discovered datasets, writing wrapper tests, or choosing valid Galaxy assertion elements and attributes. Do not use this for [[author-galaxy-tool-wrapper]], which emits UDT YAML.