diff --git a/Language/Haskell/GhcMod/GHCApi.hs b/Language/Haskell/GhcMod/GHCApi.hs
index 15bf8bf..8476b4a 100644
--- a/Language/Haskell/GhcMod/GHCApi.hs
+++ b/Language/Haskell/GhcMod/GHCApi.hs
@@ -152,7 +152,7 @@ addCmdOpts cmdOpts df =
 
 ----------------------------------------------------------------
 
--- | Set the files and load
+-- | Set the files as targets and load them.
 setTargetFiles :: (GhcMonad m) => [FilePath] -> m ()
 setTargetFiles files = do
     targets <- forM files $ \file -> G.guessTarget file Nothing
@@ -178,9 +178,11 @@ withDynFlags setFlag body = G.gbracket setup teardown (\_ -> body)
 
 ----------------------------------------------------------------
 
+-- | Set 'DynFlags' equivalent to "-w:".
 setNoWaringFlags :: DynFlags -> DynFlags
 setNoWaringFlags df = df { warningFlags = Gap.emptyWarnFlags}
 
+-- | Set 'DynFlags' equivalent to "-Wall".
 setAllWaringFlags :: DynFlags -> DynFlags
 setAllWaringFlags df = df { warningFlags = allWarningFlags }
 
diff --git a/Language/Haskell/GhcMod/Logger.hs b/Language/Haskell/GhcMod/Logger.hs
index 43563fd..6cde57e 100644
--- a/Language/Haskell/GhcMod/Logger.hs
+++ b/Language/Haskell/GhcMod/Logger.hs
@@ -44,6 +44,9 @@ appendLogRef df (LogRef ref) _ sev src style msg = do
 
 ----------------------------------------------------------------
 
+-- | Set the session flag (e.g. "-Wall" or "-w:") then
+--   executes a body. Log messages are returned as 'String'.
+--   Right is success and Left is failure.
 withLogger :: Options -> (DynFlags -> DynFlags) -> Ghc () -> Ghc (Either String String)
 withLogger opt setDF body = ghandle (handleErrMsg opt) $ do
     logref <- liftIO $ newLogRef