diff --git a/README.md b/README.md
index acc0c41..4b4499e 100644
--- a/README.md
+++ b/README.md
@@ -11,7 +11,9 @@
 
 ## Overview
 
-Encoder and decoder for arbitrary data.
+Encodes and decodes arbitrary strings to and from Base62, the alphabet of digits and lower and upper case letters,
+which keeps the encoded value compact and safe in a URL. It backs the identifiers of
+[ksuid](https://github.com/tiny-blocks/ksuid).
 
 ## Installation
 
diff --git a/composer.json b/composer.json
index bd82f37..60d70e3 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,6 @@
 {
     "name": "tiny-blocks/encoder",
-    "description": "Encoder and decoder for arbitrary data.",
+    "description": "Encodes and decodes arbitrary strings to and from Base62 for PHP.",
     "license": "MIT",
     "type": "library",
     "keywords": [