---
title: "Licence and attribution"
description: "The code is MIT and the guidance prose is separately CC BY 4.0, so a team can quote this guidance inside a clinical safety case with a clear attribution path."
url: "https://opsinjs.pensievelabs.org/project/licence-and-attribution"
source: "https://opsinjs.pensievelabs.org/project/licence-and-attribution.md"
section: "Project"
kind: "project"
reviewed: "2026-09-20"
reviewer: "engineering"
aliases: ["licence", "license", "MIT", "CC BY 4.0", "how to cite", "can I use this"]
---
> Elements written as `` below are opsinjs documentation
> components. Their attributes are the content: the values they render are
> generated from `tokens/*.json` and `registry/catalogue.ts` and are
> published separately at https://opsinjs.pensievelabs.org/r/index.json and under the Reference
> section.
> Nothing is missing from this page. The data simply does not live in
> the prose.
## Two licences, on purpose [#two-licences-on-purpose]
| What | Licence | File |
| ------------------------------------------------------------------------------------ | ------------- | -------------- |
| Source code, which covers the components, the registry, the scripts and this site | **MIT** | `LICENSE` |
| Documentation prose, which is the health, accessibility, content and design guidance | **CC BY 4.0** | `LICENSE-DOCS` |
Most projects apply one software licence to the whole repository and leave the
prose in an awkward position. That is a real problem for the people this system
is for. Teams building regulated health software quote design guidance verbatim
inside clinical safety cases, hazard logs and design-history files, and a
software licence says nothing useful about copying a paragraph into a PDF that
goes to a regulator.
Creative Commons Attribution 4.0 says it exactly: you may copy and adapt the
guidance, including commercially, provided you attribute it. There is no
share-alike obligation, so quoting a rule from this site does not place any
requirement on the rest of your document.
## Using the code [#using-the-code]
MIT. Copy it, modify it, ship it, sell what you build with it. Keep the copyright
notice. There is no warranty. In this domain that is not boilerplate, so it is
worth reading the sentence below rather than skipping it.
## Using the guidance [#using-the-guidance]
Quote it, paraphrase it, adapt it into your own internal standard, translate it.
Attribute it like this:
```text
Adapted from the opsinjs documentation (https://opsinjs.pensievelabs.org), CC BY 4.0.
```
Two things make an attribution genuinely useful to whoever reads your document
next, and neither is required by the licence:
**Name the page and its review date.** Guidance here is dated and reviewed on a
cadence. See [Docs freshness](./docs-freshness.mdx). "Adapted from *Clinical
status semantics*, reviewed 2026-09-02" tells a reviewer which version of a rule
you designed against. "Adapted from opsinjs" does not.
**Say if you changed it.** If you tightened a rule, loosened it, or applied it to
a context we did not write for, mark that. A safety reviewer must be able to tell
your judgement from ours, and you do not want to inherit the blame for a rule you
rewrote.
## What is not covered by either licence [#what-is-not-covered-by-either-licence]
* **Third-party material we cite.** Where a page references the NHS Digital
Service Manual, a journal article, WCAG, APCA or a vendor's human-interface
guidelines, that material stays under its own licence. We cite and paraphrase
in original wording; we do not reproduce. NHS content in particular is Crown
copyright and is not redistributed here. The
[Plain-English A to Z](../content/plain-english-a-z.mdx) is written from
scratch for that reason.
* **Names and trade marks.** CC BY 4.0 does not license the project's name, and
attribution is not endorsement. Do not imply that a product using this system
has been reviewed or approved by it.
* **Anything on this site marked as an opinion**, which is licensed like the rest
but is not evidence and should not be cited as though it were. Health pages
declare `evidence: cited`, `opinion` or `mixed` in their frontmatter for exactly
this reason.
## No warranty, and no clinical endorsement [#no-warranty-and-no-clinical-endorsement]
The documentation is provided as is. It is design guidance. It is not medical
advice, not a clinical safety assessment, and not a regulatory approval.
Building an interface that follows this guidance does not make that interface
safe; that judgement belongs to the team shipping the product and to its
clinical safety officer.
[Safety, scope and limitations](../start/safety-scope-and-limitations.mdx)
states the full position, including the specific regulatory claims this project
does not make.
## What we build on [#what-we-build-on]
opsinjs stands on other people's work. These are the dependencies whose licences
you inherit when you use what this project emits, verified against the versions
installed in this repository:
| Project | Licence | What it does here |
| -------------------------- | ------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- |
| Base UI (`@base-ui/react`) | MIT | The unstyled primitives every interactive component is built on, a choice explained in [ADR 0001](./decisions/0001-base-ui-not-radix.mdx) |
| React and Next.js | MIT | The framework this site runs on |
| Tailwind CSS | MIT | The utility layer the emitted components use |
| `clsx` | MIT | Half of the `cn()` helper in `@/lib/utils`, which every emitted component imports: it joins conditional class names |
| `tailwind-merge` | MIT | The other half of `cn()`: it resolves conflicting Tailwind utilities so that a class you pass in wins over the one the component set |
| fumadocs | MIT | The documentation engine, a choice explained in [ADR 0004](./decisions/0004-lyra-docs-chrome.mdx) |
| shadcn/ui | MIT | The registry specification we distribute through, and the chrome components on this site |
| Lucide | ISC | The one icon library, used for both chrome and components |
| Inter | SIL Open Font License 1.1 | The typeface of this documentation site, and not of the product theme, which uses `system-ui` |
`clsx` and `tailwind-merge` are on that list because emitted source reaches them,
not because this site does. A component copied out of the registry travels with
its own substrate. `lib/opsinjs.ts` and `lib/status.ts` are shipped as files
beside it. It imports exactly one module it does not carry: `@/lib/utils`, which
`shadcn init` writes into your project and which is those two packages and
nothing else. That is why [installing by hand](../start/installation/manual.mdx)
has you write the helper before a copied component will compile. Packages this
repository depends on but emitted code never reaches are deliberately absent:
they are our problem to license, not something you inherit.