diff --git a/src/GF/Command/Commands.hs b/src/GF/Command/Commands.hs
index 228b40c37..73730b050 100644
--- a/src/GF/Command/Commands.hs
+++ b/src/GF/Command/Commands.hs
@@ -835,7 +835,7 @@ allCommands cod env@(pgf, mos) = Map.fromList [
      _  -> fromExprs es
 
    prGrammar opts
-     | isOpt "cats"     opts = return $ fromString $ unwords $ map (showType []) $ categories pgf
+     | isOpt "cats"     opts = return $ fromString $ unwords $ map showCId $ categories pgf
      | isOpt "fullform" opts = return $ fromString $ concatMap (morpho "" prFullFormLexicon) $ optLangs opts
      | isOpt "missing"  opts = return $ fromString $ unlines $ [unwords (showCId la:":": map showCId cs) | 
                                                                   la <- optLangs opts, let cs = missingLins pgf la]
diff --git a/src/PGF.hs b/src/PGF.hs
index 1345c027d..b49a19db6 100644
--- a/src/PGF.hs
+++ b/src/PGF.hs
@@ -199,7 +199,7 @@ abstractName :: PGF -> Language
 -- | List of all categories defined in the given grammar.
 -- The categories are defined in the abstract syntax
 -- with the \'cat\' keyword.
-categories :: PGF -> [Type]
+categories :: PGF -> [CId]
 
 -- | The start category is defined in the grammar with
 -- the \'startcat\' flag. This is usually the sentence category
@@ -279,7 +279,7 @@ languages pgf = cncnames pgf
 languageCode pgf lang = 
     fmap (replace '_' '-') $ lookConcrFlag pgf lang (mkCId "language")
 
-categories pgf = [DTyp [] c (map EMeta [0..length hs]) | (c,hs) <- Map.toList (cats (abstract pgf))]
+categories pgf = [c | (c,hs) <- Map.toList (cats (abstract pgf))]
 
 startCat pgf = DTyp [] (lookStartCat pgf) []
 
diff --git a/src/server/PGFService.hs b/src/server/PGFService.hs
index c4290b7da..0a457395f 100644
--- a/src/server/PGFService.hs
+++ b/src/server/PGFService.hs
@@ -69,9 +69,8 @@ pgfMain pgf command =
             Nothing -> return Nothing
             Just "" -> return Nothing
             Just cat -> case PGF.readType cat of
-                          Nothing -> throwCGIError 400 "Bad category" ["Bad category: " ++ cat]
-                          Just typ | typ `elem` PGF.categories pgf -> return $ Just typ
-                                   | otherwise -> throwCGIError 400 "Unknown category" ["Unknown category: " ++ PGF.showType [] typ]
+                          Nothing  -> throwCGIError 400 "Bad category" ["Bad category: " ++ cat]
+                          Just typ -> return $ Just typ  -- typecheck the category
 
     getFrom :: CGI (Maybe PGF.Language)
     getFrom = getLang "from"
@@ -146,7 +145,7 @@ doGrammar pgf macc = showJSON $ toJSObject
                       ("languageCode", showJSON $ fromMaybe "" (PGF.languageCode pgf l)),
                       ("canParse",     showJSON $ PGF.canParse pgf l)]
                      | l <- PGF.languages pgf]
-        categories = map toJSObject [[("cat", PGF.showType [] cat)] | cat <- PGF.categories pgf]
+        categories = map toJSObject [[("name", PGF.showCId cat)] | cat <- PGF.categories pgf]
 
 doGraphvizAbstrTree pgf tree = do
   let dot = PGF.graphvizAbstractTree pgf (True,True) tree