diff --git a/spec/ucdn_spec.lua b/spec/ucdn_spec.lua
index 757eef1..8475b43 100644
--- a/spec/ucdn_spec.lua
+++ b/spec/ucdn_spec.lua
@@ -6,7 +6,7 @@ describe("ucdn module", function()
     assert.are_equal("8.0.0", ucdn.get_unicode_version())
   end)
 
-  it("returns the bidi class for a given codepoint", function()
+  it("returns the Bidi_Class propety value for a given codepoint", function()
     assert.are_equal(ucdn.UCDN_BIDI_CLASS_AL, ucdn.get_bidi_class(0x0627)) -- U+0627 ARABIC LETTER ALEF
     assert.are_equal(ucdn.UCDN_BIDI_CLASS_L, ucdn.get_bidi_class(0x0907))  -- U+0907 DEVANAGARI LETTER I
     assert.are_equal(ucdn.UCDN_BIDI_CLASS_WS, ucdn.get_bidi_class(0x0020)) -- U+0020 SPACE
diff --git a/src/ucdn.luadoc b/src/ucdn.luadoc
index 8e44e31..a9c5827 100644
--- a/src/ucdn.luadoc
+++ b/src/ucdn.luadoc
@@ -8,8 +8,14 @@
 -- @module ucdn
 
 --- Return version of the Unicode database.
+--  @return version string, e.g. `8.0.0`
 --  @function get_unicode_version
 
+--- Get bidirectional class of a codepoint.
+--  @param code Unicode codepoint
+--  @return value according to ucdn.UCDN_BIDI_CLASS_* and as defined in UAX#44.
+--  @function get_bidi_class
+
 --- Bidi_Class property.
 -- Enumerated constants representing [Bidi_Class values](http://www.unicode.org/reports/tr44/#Bidi_Class_Values).
 -- @section