diff --git a/src/keymap.rs b/src/keymap.rs
index 577b3b04d3519bef52b02d5954214ddf1cd230ca..3cf675b9496c9aa67aa52fb1764ecf0f74a90967 100644
--- a/src/keymap.rs
+++ b/src/keymap.rs
@@ -1,3 +1,4 @@
+//! Bindings from keys to command for Emacs and Vi modes
 use config::Config;
 use config::EditMode;
 use consts::KeyPress;
diff --git a/src/undo.rs b/src/undo.rs
index b74737fccfef521fc7eec20610cf0450a56463c7..5c6128c8da63ff04190e137b50d1494ce43135ac 100644
--- a/src/undo.rs
+++ b/src/undo.rs
@@ -1,3 +1,4 @@
+//! Undo API
 use line_buffer::LineBuffer;
 use std_unicode::str::UnicodeStr;
 use unicode_segmentation::UnicodeSegmentation;