diff --git a/HISTORY.md b/HISTORY.md
index 131114a4c..b7252d7f9 100755
--- a/HISTORY.md
+++ b/HISTORY.md
@@ -6,6 +6,11 @@
     * new "input slots" menu option for custom block input slots 
 * **Notable Changes:**
     * automatically add a dropdown menu to any custom block input slot whose definition has a slot menu event hat block for it
+* **Notable Fixes:**
+    * fixed input names when querying a custom block definition that has no function body script
+
+### 2024-11-12
+* threads: fixed input names when querying a custom block definition that has no function body script
 
 ### 2024-11-11
 * threads: expose a copy of the custom block as "caller" to input slot reaction scripts inside custom block definitions
diff --git a/snap.html b/snap.html
index 738209ea0..7e682233e 100755
--- a/snap.html
+++ b/snap.html
@@ -17,7 +17,7 @@
         <script src="src/symbols.js?version=2024-09-13"></script>
         <script src="src/widgets.js?version=2024-07-24"></script>
         <script src="src/blocks.js?version=2024-11-11"></script>
-        <script src="src/threads.js?version=2024-11-11"></script>
+        <script src="src/threads.js?version=2024-11-12"></script>
         <script src="src/objects.js?version=2024-11-10"></script>
         <script src="src/scenes.js?version=2024-05-28"></script>
         <script src="src/gui.js?version=2024-11-10"></script>
diff --git a/src/threads.js b/src/threads.js
index 5a889b90f..13bb01ffa 100644
--- a/src/threads.js
+++ b/src/threads.js
@@ -65,7 +65,7 @@ StagePickerMorph, CustomBlockDefinition, CommentMorph, BooleanSlotMorph*/
 
 /*jshint esversion: 11, bitwise: false, evil: true*/
 
-modules.threads = '2024-November-11';
+modules.threads = '2024-November-12';
 
 var ThreadManager;
 var Process;
@@ -7972,19 +7972,24 @@ Process.prototype.reportBasicBlockAttribute = function (attribute, block) {
     case 'definition':
         if (expr.isCustomBlock) {
             if (expr.isGlobal) {
-                if (expr.definition.primitive && !expr.definition.body) {
+                def = expr.definition;
+                if (def.primitive && !def.body) {
                     prim = SpriteMorph.prototype.blockForSelector(
                         'doPrimitive'
                     );
                     prim.inputs()[0].setContents(true);
-                    prim.inputs()[1].setContents(expr.definition.primitive);
+                    prim.inputs()[1].setContents(def.primitive);
                     body = prim.reify();
-                } else {
-                    body = expr.definition.body || new Context();
                 }
             } else {
-                body = this.blockReceiver().getMethod(expr.semanticSpec).body ||
-                    new Context();
+                def = this.blockReceiver().getMethod(expr.semanticSpec);
+            }
+            if (!body) {
+                body = def.body;
+                if (!body) {
+                    body = new Context();
+                    def.inputNames().forEach(name => body.addInput(name));
+                }
             }
         } else {
             prim = SpriteMorph.prototype.blocks[expr.selector].src;
@@ -7997,14 +8002,14 @@ Process.prototype.reportBasicBlockAttribute = function (attribute, block) {
                 prim.inputs()[1].setContents(expr.selector);
                 body = prim.reify();
             }
-        }
-        if (body instanceof Context &&
-            (!body.expression || prim) &&
-            !body.inputs.length
-        ) {
-            // make sure the definition has the same number of inputs as the
-            // block prototype (i.e. the header)
-            expr.inputs().forEach((inp, i) => body.addInput('#' + (i + 1)));
+            if (body instanceof Context &&
+                (!body.expression || prim) &&
+                !body.inputs.length
+            ) {
+                // make sure the definition has the same number of inputs as the
+                // block prototype (i.e. the header)
+                expr.inputs().forEach((inp, i) => body.addInput('#' + (i + 1)));
+            }
         }
         if (body.expression && body.expression.selector === 'doReport' &&
                 body.expression.inputs()[0] instanceof BlockMorph) {