Update README

README.md

@@ -1,2 +1,30 @@
 # setup-supercollider
-Setup your GitHub Actions workflow with SuperCollider from source
+
+Setup your GitHub Actions workflow with headless SuperCollider built from
+source.
+
+Validated to work on GitHub's standard `macos-15`, `ubuntu-latest`, and
+`windows-latest` runners.
+
+## Inputs
+
+| Title   | Required | Type   | Default                                              | Description                  |
+|---------|----------|--------|------------------------------------------------------|------------------------------|
+| origin  | False    | string | `https://github.com/supercollider/supercollider.git` | SuperCollider repository URL |
+| ref     | False    | string | `develop`                                            | SuperCollider branch/tag ref |
+
+## Outputs
+
+| Title          | Type   | Description                  |
+|----------------|--------|------------------------------|
+| sclang_path    | string | path to `sclang` binary      |
+| scsynth_path   | string | path to `scsynth` binary     |
+| supernova_path | string | path to `supernova` binary   |
+
+## Caching
+
+Windows workflows will automatically cache `vcpkg` archives.
+
+We strongly recommend you also use https://github.com/hendrikmuhs/ccache-action
+to prior to running this action in order to cache `ccache` for additional
+speedups.

action.yaml

@@ -10,7 +10,7 @@ inputs:
     required: false
     default: https://github.com/supercollider/supercollider.git
   ref:
-    description: SuperCollider ref
+    description: SuperCollider branch/tag ref
     required: false
     default: develop
 outputs: