diff --git a/src/Database.zig b/src/Database.zig
index 8edd0aa..ba8125d 100644
--- a/src/Database.zig
+++ b/src/Database.zig
@@ -371,7 +371,13 @@ test create {
     try std.testing.expect(r == .ok);
 }
 
-pub const CloseError = error{ XapianException, Unexpected };
+pub const CloseError = error{
+    /// A Xapian exception occurred. The database has still been closed, but
+    /// there is no guarantee that any changes were flushed to disk.
+    XapianException,
+    /// libnotmuch returned an undocumented status code.
+    Unexpected,
+};
 
 /// Commit changes and close the given notmuch database.
 ///
diff --git a/src/Directory.zig b/src/Directory.zig
index a051339..c1c284d 100644
--- a/src/Directory.zig
+++ b/src/Directory.zig
@@ -56,6 +56,7 @@ pub fn getMtime(self: *const Directory) ?i64 {
 }
 
 pub const GetChildFilesError = error{
+    /// A Xapian exception occurred.
     XapianException,
 };
 
@@ -71,6 +72,7 @@ pub fn getChildFiles(self: *const Directory) GetChildFilesError!FilenamesIterato
 }
 
 pub const GetChildDirectoriesError = error{
+    /// A Xapian exception occurred.
     XapianException,
 };
 
diff --git a/src/Message.zig b/src/Message.zig
index 631f48f..bbfd8eb 100644
--- a/src/Message.zig
+++ b/src/Message.zig
@@ -98,6 +98,7 @@ pub fn countFiles(self: *const Message) CountFilesError!usize {
 }
 
 pub const GetFilenameError = error{
+    /// A Xapian exception occurred.
     XapianException,
 };
 
@@ -121,6 +122,7 @@ pub fn getFilename(self: *const Message) GetFilenameError![:0]const u8 {
 }
 
 pub const GetFilenamesError = error{
+    /// A Xapian exception occurred.
     XapianException,
 };
 
@@ -158,6 +160,7 @@ pub fn reindex(self: *const Message, indexopts: ?IndexOpts) Error!void {
 }
 
 pub const GetFlagError = error{
+    /// A Xapian exception occurred.
     XapianException,
     /// libnotmuch returned an undocumented status code.
     Unexpected,
@@ -270,6 +273,7 @@ pub fn removeTag(self: *const Message, tag: [:0]const u8) RemoveTagError!void {
 pub const RemoveAllTagsError = error{
     /// Database was opened in read-only mode so message cannot be modified.
     ReadOnlyDatabase,
+    /// A Xapian exception occurred.
     XapianException,
     /// libnotmuch returned an undocumented status code.
     Unexpected,
@@ -320,6 +324,7 @@ pub fn maildirFlagsToTags(self: *const Message) Error!void {
 }
 
 pub const HasMaildirFlagError = error{
+    /// A Xapian exception occurred.
     XapianException,
     /// libnotmuch returned an undocumented status code.
     Unexpected,