diff --git a/config.nims b/config.nims
index d35a93d..08448f8 100644
--- a/config.nims
+++ b/config.nims
@@ -72,7 +72,7 @@ task clean, "Remove all generated files":
 
 task server, "Compile server daemon":
   --d:release
-  --d:yamlScalarRepInd
+  --stackTrace
   setCommand "c", "server/server"
 
 task testSuiteEvents, "Compile the testSuiteEvents tool":
diff --git a/flake.nix b/flake.nix
index bffc53c..a0600c7 100644
--- a/flake.nix
+++ b/flake.nix
@@ -94,7 +94,7 @@
                 proc shareDir*(): string =
                   result = "$out/share"
                 EOF
-                ${pkgs.nim}/bin/nim c --d:release --d:yamlScalarRepInd -p:"${nim-jester}/lib" -p:"${nim-httpbeast}/lib" -p:"${nim-cligen}/lib" --nimcache:.cache server/server
+                ${pkgs.nim}/bin/nim c --d:release --stackTrace -p:"${nim-jester}/lib" -p:"${nim-httpbeast}/lib" -p:"${nim-cligen}/lib" --nimcache:.cache server/server
               '';
               installPhase = ''
                 mkdir -p $out/{bin,share}
diff --git a/server/server.nim b/server/server.nim
index caf14e0..4b958fc 100644
--- a/server/server.nim
+++ b/server/server.nim
@@ -28,15 +28,18 @@ router nyRouter:
       of "json": style = psJson
       of "block": style = psBlockOnly
       of "tokens":
-        var
-          output = "+STR\n"
-          parser = initYamlParser(false)
-          events = parser.parse(newStringStream(@"input"))
-        for event in events: output.add(parser.display(event) & "\n")
-        output &= "-STR"
-        resultNode["code"] = %0
-        resultNode["output"] = %output
-        msg = resultNode.pretty
+        try:
+          var
+            output = "+STR\n"
+            parser = initYamlParser(false)
+            events = parser.parse(newStringStream(@"input"))
+          for event in events: output.add(parser.display(event) & "\n")
+          output &= "-STR"
+          resultNode["code"] = %0
+          resultNode["output"] = %output
+          msg = resultNode.pretty
+        except YamlStreamError as e:
+          raise e.parent
       else:
         retStatus = Http400
         msg = "Invalid style: " & escape(@"style")