# Plugins

Nodes come from **plugins**. noodlelab ships with its own (units, uncertainty,
maths, science, engineering, geo, machine learning...), and anyone can write
more and publish them from a git repository, without asking anyone.

A plugin is an ordinary Python package with:

- a `noodlelab.nodes` entry point, whose name prefixes its node ids
  (`thermo.rankine_cycle`);
- a manifest, `noodlelab-plugin.toml`, that names it, states the plugin API it
  was written for, the other plugins it needs and what it does besides
  computing;
- code that uses noodlelab only through {mod}`noodlelab.plugin`, the public
  API.

Plugins are versioned as a whole, with git tags (`v1.4.2`, semantic
versioning). A plugin can require others (`requires = { maths = ">=1.2,<2" }`):
adding it adds them. Every run's provenance records each plugin's version and
the git commit it was built from, and every saved graph records the plugins it
needs, so it can be opened elsewhere with the same code.

- [Installing plugins](installing.md): in the admin portal, on the command
  line, in Python and from agents
- [Writing a plugin](writing.md): the standard, the manifest and the public API
- [Publishing a plugin](publishing.md): versions, signed releases and indexes
- [Security](security.md): what protects you from a harmful plugin, and what
  does not

```{toctree}
:hidden:

installing
writing
publishing
security
```