diff --git a/internal/attribgen/README.md b/internal/attribgen/README.md
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+# attribgen
+
+attribgen reads simple descriptions of HTML element attributes from
+`attribs.txt` and generates Go functions to create them. The file contains
+one description per line. Each description is in the form
+```
+attribute-name attribute-type
+```
+where `attribute-name` is the lowercase name of the attribute, and
+`attribute-type` is either `string` for normal attributes (e.g. `id`, 'style')
+or `bool` for boolean attributes (e.g. `disabled`).
diff --git a/internal/elementgen/README.md b/internal/elementgen/README.md
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+# elementgen
+
+elementgen reads simple descriptions of HTML elements from `elements.txt`
+and generates Go functions to create them. The file contains one description
+per line. Each description is in the form
+```
+tag-name element-type
+```
+where `tag-name` is the lowercase name of the element, and `element-type` is
+either `empty` for empty elements (e.g. `img`, 'br') or `parent` for elements
+that can have child nodes (e.g. 'div', 'body').