diff --git a/tools/cheddar/README.md b/tools/cheddar/README.md
index 96faa34a4..706f3b62d 100644
--- a/tools/cheddar/README.md
+++ b/tools/cheddar/README.md
@@ -4,6 +4,17 @@ cheddar
 Cheddar is a tiny Rust tool that uses [syntect][] to render source code to
 syntax-highlighted HTML.
 
+It's invocation is compatible with `cgit` filters, i.e. data is read from
+`stdin` and the filename is taken from `argv`:
+
+```shell
+cat README.md | cheddar README.md > README.html
+
+```
+
+In fact, if you are looking at this file on git.tazj.in chances are that it was
+rendered by cheddar.
+
 The name was chosen because I was eyeing a pack of cheddar-flavoured crisps
 while thinking about name selection.