diff --git a/Database/Cayley/Client.hs b/Database/Cayley/Client.hs
--- a/Database/Cayley/Client.hs
+++ b/Database/Cayley/Client.hs
@@ -82,7 +82,7 @@
 -- | Return the description of the given executed query.
 queryShape :: CayleyConnection
            -> Query
-           -> IO (A.Result Shape)
+           -> IO (Either String Shape)
 queryShape c q =
   runReaderT (doShape (getManager c) (encodeUtf8 q)) (getConfig c)
   where
@@ -93,8 +93,11 @@
              serverPort (RequestBodyBS _q)
       return $
         case r of
-          Just o  -> A.fromJSON o
-          Nothing -> A.Error "API request error"
+          Just o  ->
+            case A.fromJSON o of
+              A.Success s -> Right s
+              A.Error e   -> Left ("Not a shape (\"" ++ e ++ "\")")
+          Nothing -> Left "API request error"
 
 -- | Write a 'Quad' with the given subject, predicate, object and optional
 -- label. Throw result or extract amount of query 'results'
diff --git a/cayley-client.cabal b/cayley-client.cabal
--- a/cayley-client.cabal
+++ b/cayley-client.cabal
@@ -1,5 +1,5 @@
 name: cayley-client
-version: 0.3.3
+version: 0.4.0
 cabal-version: >=1.10
 build-type: Simple
 license: BSD3
@@ -52,8 +52,8 @@
     build-depends:
         hspec >=2.1.10 && <2.5,
         base >=4.8 && <5,
-        cayley-client >=0.3.3 && <0.4,
-        aeson >=0.8.0.2 && <1.1,
+        cayley-client >=0.4.0 && <0.5,
+        aeson >=0.8.0.2 && <1.2,
         unordered-containers >=0.2.5 && <0.3
     default-language: Haskell2010
     hs-source-dirs: tests
diff --git a/tests/hspec.hs b/tests/hspec.hs
--- a/tests/hspec.hs
+++ b/tests/hspec.hs
@@ -12,18 +12,18 @@
     describe "write" $
         it "writes a quad to Cayley server" $ do
             c <- connectCayley defaultCayleyConfig
-            write c Quad { subject = "danny", predicate = "follows", C.object = "sandy", label = Nothing } `shouldReturn` Just (Object (fromList [("result",String "Successfully wrote 1 quads.")]))
+            write c Quad { subject = "<danny>", predicate = "<follows>", C.object = "<sandy>", label = Nothing } `shouldReturn` Just (Object (fromList [("result",String "Successfully wrote 1 quads.")]))
 
     describe "query" $
         it "query Cayley server" $ do
             c <- connectCayley defaultCayleyConfig
-            Right a <- query c "graph.Vertex('sandy').In('follows').All()"
-            encode a `shouldBe` "[{\"id\":\"danny\"}]"
+            Right a <- query c "graph.Vertex('<sandy>').In('<follows>').All()"
+            encode a `shouldBe` "[{\"id\":\"<danny>\"}]"
 
     describe "shape" $
         it "returns the description of the last query executed" $ do
             c <- connectCayley defaultCayleyConfig
-            queryShape c "graph.Vertex('sandy').In('follows').All()" `shouldReturn` Success (Shape {nodes = [Node {CT.id = 4, tags = Nothing, values = Just ["sandy"], isLinkNode = False, isFixed = True},Node {CT.id = 8, tags = Nothing, values = Just ["follows"], isLinkNode = False, isFixed = True},Node {CT.id = 2, tags = Nothing, values = Nothing, isLinkNode = True, isFixed = False},Node {CT.id = 1, tags = Just ["id"], values = Nothing, isLinkNode = False, isFixed = False}], links = [Link {source = 1, target = 4, linkNode = 2}]})
+            queryShape c "graph.Vertex('<sandy>').In('<follows>').All()" `shouldReturn` Right (Shape {nodes = [Node {CT.id = 4, tags = Nothing, values = Just ["<sandy>"], isLinkNode = False, isFixed = True},Node {CT.id = 8, tags = Nothing, values = Just ["<follows>"], isLinkNode = False, isFixed = True},Node {CT.id = 2, tags = Nothing, values = Nothing, isLinkNode = True, isFixed = False},Node {CT.id = 1, tags = Just ["id"], values = Nothing, isLinkNode = False, isFixed = False}], links = [Link {source = 1, target = 4, linkNode = 2}]})
 
     describe "writeNQuadFile" $
         it "writes quads from a file to Cayley server" $ do