diff --git a/AresScript.Tests/Program.cs b/AresScript.Tests/Program.cs
index a5b3b4a5..b3d74d8d 100644
--- a/AresScript.Tests/Program.cs
+++ b/AresScript.Tests/Program.cs
@@ -218,6 +218,31 @@ public Task SyntaxErrors_AreThrown()
     return Task.CompletedTask;
   }
 
+  [Test]
+  public async Task Validation_AllowsMemberAccess_OnUnknownFunctionParameter()
+  {
+    var script = """
+      def meme(bepis):
+        bepis.GetTemperature()
+      """;
+
+    await ValidateScriptAsync(script);
+  }
+
+  [Test]
+  public async Task Validation_AssignsVariable_FromUserFunctionCall()
+  {
+    var script = """
+      def main():
+        return 1
+
+      bepis = main()
+      assert bepis == 1
+      """;
+
+    await ValidateScriptAsync(script);
+  }
+
   [Test]
   public async Task Range_OneArg_GeneratesCorrectSequence()
   {
diff --git a/AresScript/Interpreters/AresValidationInterpreter.cs b/AresScript/Interpreters/AresValidationInterpreter.cs
index 34782e25..4653db70 100644
--- a/AresScript/Interpreters/AresValidationInterpreter.cs
+++ b/AresScript/Interpreters/AresValidationInterpreter.cs
@@ -121,7 +121,7 @@ public override async Task VisitFuncBlock(AresLangParser.FuncBlockContext contex
       {
         foreach(var parameter in _pendingFunctionParameters.Peek())
         {
-          _environment.AssignVariable(parameter, AresValueHelper.CreateNull());
+          _environment.AssignVariable(parameter, CreateUnknownValue());
         }
       }
 
@@ -461,7 +461,7 @@ public override async Task VisitLambdaExpr(AresLangParser.LambdaExprContext cont
     {
       foreach(var parameter in parameterNames)
       {
-        _environment.AssignVariable(parameter, AresValueHelper.CreateNull());
+        _environment.AssignVariable(parameter, CreateUnknownValue());
       }
 
       await Visit(body);
@@ -495,6 +495,7 @@ public override Task VisitMemberAccess([NotNull] AresLangParser.MemberAccessCont
   {
     var ctxExpr = context.expression();
     var id = context.ID().GetText();
+    var receiverSchema = _typeInference.Visit(ctxExpr);
     if(!TryResolveValue(ctxExpr, out var value))
     {
       throw new AresInterpreterException(
@@ -513,6 +514,11 @@ public override Task VisitMemberAccess([NotNull] AresLangParser.MemberAccessCont
       );
     }
 
+    if(receiverSchema.Type is AresDataType.Any or AresDataType.UnspecifiedType)
+    {
+      return Task.CompletedTask;
+    }
+
     if(value.KindCase == AresValue.KindOneofCase.StructValue)
     {
       if(value.StructValue.Fields.ContainsKey(id))
@@ -533,6 +539,12 @@ public override Task VisitMemberAccess([NotNull] AresLangParser.MemberAccessCont
     );
   }
 
+  private static AresValue CreateUnknownValue()
+  {
+    // A value with no active oneof kind maps to UnspecifiedType in schema inference.
+    return new AresValue();
+  }
+
   public override async Task VisitFunctionCall(AresLangParser.FunctionCallContext ctx)
   {
     var ctxExpr = ctx.expression();
@@ -1028,12 +1040,29 @@ private static int FindParameterIndex(IReadOnlyList<string> parameters, string n
       case AresLangParser.FunctionCallContext functionCallContext:
         {
           var funcId = TryResolveFunctionId(functionCallContext.expression());
-          if(funcId is not null && _environment.TryGetSystemFunction(funcId, out var systemFunction))
+          if(funcId is null)
+          {
+            break;
+          }
+
+          if(_environment.TryGetValue(funcId, out var aliasValue) && aliasValue.FunctionValue is not null)
+          {
+            funcId = aliasValue.FunctionValue.FunctionId;
+          }
+
+          if(_environment.TryGetSystemFunction(funcId, out var systemFunction))
           {
             var schema = systemFunction.OutputSchema;
             var dummyValue = InterpreterHelpers.CreateDummyValue(schema);
             return dummyValue;
           }
+
+          if(_environment.TryGetUserFunction(funcId, out var _) || _environment.TryGetUserLambda(funcId, out var _))
+          {
+            // We cannot know user-function return shape statically in this pass, but assignment target
+            // should still be introduced into scope for subsequent validation.
+            return CreateUnknownValue();
+          }
           break;
         }
     }
diff --git a/UI/Components/ScriptEditor.razor b/UI/Components/ScriptEditor.razor
index 71f14983..a2199406 100644
--- a/UI/Components/ScriptEditor.razor
+++ b/UI/Components/ScriptEditor.razor
@@ -5,6 +5,7 @@
 <StandaloneCodeEditor CssClass="h-100" @ref="_editor" Id="ares-editor" ConstructionOptions="EditorConstructionOptions" />
 
 @code {
+  private const string DefaultScript = "# Welcome to ARES\ndef main():\n    return True\n";
   private StandaloneCodeEditor _editor;
 
   private IJSObjectReference? _setupModule;
@@ -30,8 +31,21 @@
   [Parameter]
   public IMonacoHoverProvider? HoverProvider { get; set; }
 
+  [Parameter]
+  public string? InitialScript { get; set; }
+
   public Task<string> GetScript() => _editor.GetValue();
 
+  public async Task SetScript(string script)
+  {
+    if(_editor is null)
+    {
+      return;
+    }
+
+    await _editor.SetValue(script ?? string.Empty);
+  }
+
   protected override async Task OnAfterRenderAsync(bool firstRender)
   {
     if(firstRender)
@@ -129,13 +143,14 @@
 
   private StandaloneEditorConstructionOptions EditorConstructionOptions(StandaloneCodeEditor editor)
   {
+    var initialScript = string.IsNullOrWhiteSpace(InitialScript) ? DefaultScript : InitialScript;
+
     return new StandaloneEditorConstructionOptions
     {
       Language = "ares",
       AutomaticLayout = true,
       SemanticHighlightingEnabled = true,
-      Value = "# Welcome to ARES\ndef main():\n    return True\n"
+      Value = initialScript
     };
   }
 }
-