diff --git a/dataspace/edc/agent-plane/agent-plane-protocol/src/main/java/io/catenax/knowledge/dataspace/edc/sparql/SkillVariableDetector.java b/dataspace/edc/agent-plane/agent-plane-protocol/src/main/java/io/catenax/knowledge/dataspace/edc/sparql/SkillVariableDetector.java
new file mode 100644
index 00000000..210b3c2e
--- /dev/null
+++ b/dataspace/edc/agent-plane/agent-plane-protocol/src/main/java/io/catenax/knowledge/dataspace/edc/sparql/SkillVariableDetector.java
@@ -0,0 +1,56 @@
+//
+// EDC Data Plane Agent Extension
+// See copyright notice in the top folder
+// See authors file in the top folder
+// See license file in the top folder
+//
+package io.catenax.knowledge.dataspace.edc.sparql;
+
+import org.apache.jena.graph.Node;
+import org.apache.jena.sparql.algebra.Op;
+import org.apache.jena.sparql.algebra.TransformSingle;
+import org.apache.jena.sparql.algebra.op.OpExtend;
+import org.apache.jena.sparql.core.Var;
+import org.apache.jena.sparql.expr.ExprVar;
+import org.apache.jena.sparql.expr.nodevalue.NodeValueNode;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * a pseudo transform which visits every graph node
+ * to list all variables. helps us to
+ * only serialize the needed portion from
+ * consumer to producer
+ */
+public class SkillVariableDetector extends TransformSingle {
+
+    HashMap<String,Node> variables=new HashMap<>();
+    Set<String> allowed;
+
+    public SkillVariableDetector(Set<String> allowed) {
+        this.allowed=allowed;
+    }
+
+    @Override
+    public Op transform(OpExtend opExtend, Op subOp) {
+        opExtend.getVarExprList().forEachExpr( (assignment,expr) -> {
+            String varName= assignment.getVarName();
+            if(allowed.contains(varName) && !variables.containsKey(varName)) {
+                if(expr.isVariable()) {
+                    Var var = (Var) ((ExprVar)expr).getAsNode();
+                    variables.put(varName, var);
+                } else if(expr.isConstant()) {
+                    Node node = ((NodeValueNode) expr).getNode();
+                    variables.put(varName, node);
+                }
+            }
+        });
+        return opExtend;
+    }
+
+    public Map<String,Node> getVariables() {
+        return variables;
+    }
+}