diff --git a/libs/luna-empire/src/Empire/ASTOps/Read.hs b/libs/luna-empire/src/Empire/ASTOps/Read.hs
index c3023834e777..c9102e5649c1 100644
--- a/libs/luna-empire/src/Empire/ASTOps/Read.hs
+++ b/libs/luna-empire/src/Empire/ASTOps/Read.hs
@@ -323,6 +323,9 @@ isCons expr = isJust <$> IRExpr.narrowTerm @IR.Cons expr
 isVar :: GraphOp m => NodeRef -> m Bool
 isVar expr = isJust <$> IRExpr.narrowTerm @IR.Var expr
 
+isASGFunction :: GraphOp m => NodeRef -> m Bool
+isASGFunction expr = isJust <$> IRExpr.narrowTerm @IR.ASGFunction expr
+
 dumpPatternVars :: GraphOp m => NodeRef -> m [NodeRef]
 dumpPatternVars ref = match ref $ \case
     Var _     -> return [ref]
diff --git a/libs/luna-empire/src/Empire/Commands/GraphBuilder.hs b/libs/luna-empire/src/Empire/Commands/GraphBuilder.hs
index 98bded7d8a19..6fabd53ecc52 100644
--- a/libs/luna-empire/src/Empire/Commands/GraphBuilder.hs
+++ b/libs/luna-empire/src/Empire/Commands/GraphBuilder.hs
@@ -415,16 +415,17 @@ buildConnections = do
 
 buildInputSidebarTypecheckUpdate :: GraphOp m => NodeId -> m API.NodeTypecheckerUpdate
 buildInputSidebarTypecheckUpdate nid = do
-    API.InputSidebar nid ps <- buildInputSidebar nid
+    API.InputSidebar nid ps _ <- buildInputSidebar nid
     pure $ API.InputSidebarUpdate nid ps
 
 
 buildInputSidebar :: GraphOp m => NodeId -> m API.InputSidebar
 buildInputSidebar nid = do
     ref      <- ASTRead.getCurrentASTTarget
+    isDef    <- ASTRead.isASGFunction ref
     args     <- ASTDeconstruct.extractFunctionPorts ref
     argTrees <- zipWithM buildOutPortTree (pure . Projection <$> [0..]) args
-    pure $ API.InputSidebar nid argTrees
+    pure $ API.InputSidebar nid argTrees isDef
 
 buildOutputSidebarTypecheckUpdate :: GraphOp m => NodeId -> m API.NodeTypecheckerUpdate
 buildOutputSidebarTypecheckUpdate nid = do
diff --git a/libs/luna-empire/test/EmpireSpec.hs b/libs/luna-empire/test/EmpireSpec.hs
index d93d590c2e4c..593ae050bdab 100644
--- a/libs/luna-empire/test/EmpireSpec.hs
+++ b/libs/luna-empire/test/EmpireSpec.hs
@@ -76,6 +76,7 @@ spec = around withChannels $ parallel $ do
                 length topLevel `shouldBe` 1
                 topLevel `shouldContain` [u1]
                 i            `shouldSatisfy` isJust
+                i ^? _Just . Node.isDef `shouldBe` Just False
                 o            `shouldSatisfy` isJust
                 n1LevelNodes `shouldSatisfy` null
         it "asserts things about `foo = a: a`" $ \env -> do
diff --git a/libs/luna-empire/test/FileLoadSpec.hs b/libs/luna-empire/test/FileLoadSpec.hs
index e28ea8e05711..3ee97a6f2630 100644
--- a/libs/luna-empire/test/FileLoadSpec.hs
+++ b/libs/luna-empire/test/FileLoadSpec.hs
@@ -173,7 +173,7 @@ spec = around withChannels $ parallel $ do
                 let loc' = GraphLocation "TestPath" $ Breadcrumb [Definition (main ^. Node.nodeId)]
                 graph <- Graph.withGraph loc' $ runASTOp $ GraphBuilder.buildGraph
                 return graph
-            withResult res $ \(Graph.Graph nodes connections _ _ _) -> do
+            withResult res $ \(Graph.Graph nodes connections i _ _) -> do
                 let Just pi = find (\node -> node ^. Node.name == Just "pi") nodes
                 pi ^. Node.code `shouldBe` "3.14"
                 pi ^. Node.canEnter `shouldBe` False
@@ -189,6 +189,7 @@ spec = around withChannels $ parallel $ do
                 let Just c = find (\node -> node ^. Node.name == Just "c") nodes
                 c ^. Node.code `shouldBe` "3"
                 c ^. Node.canEnter `shouldBe` False
+                i ^? _Just . Node.isDef `shouldBe` Just True
                 connections `shouldMatchList` [
                       (outPortRef (pi ^. Node.nodeId)  [], inPortRef (anon ^. Node.nodeId) [Port.Arg 0])
                     , (outPortRef (foo ^. Node.nodeId) [], inPortRef (bar  ^. Node.nodeId) [Port.Head])
@@ -1402,7 +1403,7 @@ spec = around withChannels $ parallel $ do
                         «1»d = foo 3
                         d
                     |]
-            code <- evalEmp env $ do
+            (inputSidebar, code) <- evalEmp env $ do
                 Library.createLibrary Nothing "TestPath"
                 let loc = GraphLocation "TestPath" $ Breadcrumb []
                 Graph.loadCode loc initialCode
@@ -1414,7 +1415,9 @@ spec = around withChannels $ parallel $ do
                 (input, _) <- Graph.withGraph loc'' $ runASTOp $ GraphBuilder.getEdgePortMapping
                 Graph.removePort loc'' (outPortRef input [Port.Projection 0])
                 code <- Graph.withUnit loc $ use Graph.code
-                return code
+                inputSidebar <- Graph.withGraph loc'' $ runASTOp $ GraphBuilder.buildInputSidebar input
+                return (inputSidebar, code)
+            inputSidebar ^. Node.isDef `shouldBe` True
             normalizeQQ (Text.unpack code) `shouldBe` normalizeQQ [r|
                 def main:
                     «2»def foo:
diff --git a/libs/luna-studio-common/src/LunaStudio/Data/Node.hs b/libs/luna-studio-common/src/LunaStudio/Data/Node.hs
index 2aaa3653f489..c04e033c7056 100644
--- a/libs/luna-studio-common/src/LunaStudio/Data/Node.hs
+++ b/libs/luna-studio-common/src/LunaStudio/Data/Node.hs
@@ -32,6 +32,7 @@ data ExpressionNode = ExpressionNode { _exprNodeId       :: NodeId
 
 data InputSidebar = InputSidebar { _inputNodeId    :: NodeId
                                  , _inputEdgePorts :: [OutPortTree OutPort]
+                                 , _isDef          :: Bool
                                  } deriving (Eq, Generic, Show, Typeable)
 
 data OutputSidebar = OutputSidebar { _outputNodeId    :: NodeId