diff --git a/core/src/main/java/io/xpipe/core/data/generic/GenericDataStreamParser.java b/core/src/main/java/io/xpipe/core/data/generic/GenericDataStreamParser.java
index 1cba03a5..dcef8607 100644
--- a/core/src/main/java/io/xpipe/core/data/generic/GenericDataStreamParser.java
+++ b/core/src/main/java/io/xpipe/core/data/generic/GenericDataStreamParser.java
@@ -10,71 +10,75 @@ import java.util.List;
 
 public class GenericDataStreamParser {
 
-    public static DataStructureNode read(InputStream in) throws IOException {
+    public static DataStructureNode parse(InputStream in) throws IOException {
         var reader = new GenericDataStructureNodeReader();
-        read(in, reader);
+        parse(in, reader);
         return reader.create();
     }
 
-    public static List<DataStructureNode> readN(InputStream in, int n) throws IOException {
+    public static List<DataStructureNode> parseN(InputStream in, int n) throws IOException {
         var list = new ArrayList<DataStructureNode>();
         var reader = new GenericDataStructureNodeReader();
         for (int i = 0; i < n; i++) {
-            read(in, reader);
+            parse(in, reader);
             list.add(reader.create());
         }
         return list;
     }
 
-    public static void read(InputStream in, GenericDataStreamCallback cb) throws IOException {
+    public static void parse(InputStream in, GenericDataStreamCallback cb) throws IOException {
         var b = in.read();
         if (b == -1) {
             return;
         }
 
+        if (b == DataStructureNodeIO.GENERIC_STRUCTURE_ID) {
+            b = in.read();
+        }
+
         switch (b) {
             case DataStructureNodeIO.GENERIC_TUPLE_ID -> {
-                readTuple(in, cb);
+                parseTuple(in, cb);
             }
             case DataStructureNodeIO.GENERIC_ARRAY_ID -> {
-                readArray(in, cb);
+                parseArray(in, cb);
             }
             case DataStructureNodeIO.GENERIC_VALUE_ID -> {
-                readValue(in, cb);
+                parseValue(in, cb);
             }
             case DataStructureNodeIO.GENERIC_NAME_ID -> {
-                readName(in, cb);
-                read(in, cb);
+                parseName(in, cb);
+                parse(in, cb);
             }
             default -> throw new IllegalStateException("Unexpected type id: " + b);
         }
     }
 
-    private static void readName(InputStream in, GenericDataStreamCallback cb) throws IOException {
+    private static void parseName(InputStream in, GenericDataStreamCallback cb) throws IOException {
         var nameLength = in.read();
         var name = new String(in.readNBytes(nameLength));
         cb.onName(name);
     }
 
-    private static void readTuple(InputStream in, GenericDataStreamCallback cb) throws IOException {
+    private static void parseTuple(InputStream in, GenericDataStreamCallback cb) throws IOException {
         var size = in.read();
         cb.onTupleStart(size);
         for (int i = 0; i < size; i++) {
-            read(in, cb);
+            parse(in, cb);
         }
         cb.onTupleEnd();
     }
 
-    private static void readArray(InputStream in, GenericDataStreamCallback cb) throws IOException {
+    private static void parseArray(InputStream in, GenericDataStreamCallback cb) throws IOException {
         var size = in.read();
         cb.onArrayStart(size);
         for (int i = 0; i < size; i++) {
-            read(in, cb);
+            parse(in, cb);
         }
         cb.onArrayEnd();
     }
 
-    private static void readValue(InputStream in, GenericDataStreamCallback cb) throws IOException {
+    private static void parseValue(InputStream in, GenericDataStreamCallback cb) throws IOException {
         var size = in.read();
         var data = in.readNBytes(size);
         cb.onValue(data);
diff --git a/core/src/main/java/io/xpipe/core/data/generic/GenericDataStreamWriter.java b/core/src/main/java/io/xpipe/core/data/generic/GenericDataStreamWriter.java
index 5f8adfe2..13449799 100644
--- a/core/src/main/java/io/xpipe/core/data/generic/GenericDataStreamWriter.java
+++ b/core/src/main/java/io/xpipe/core/data/generic/GenericDataStreamWriter.java
@@ -1,9 +1,6 @@
 package io.xpipe.core.data.generic;
 
-import io.xpipe.core.data.node.DataStructureNode;
-import io.xpipe.core.data.node.ArrayNode;
-import io.xpipe.core.data.node.TupleNode;
-import io.xpipe.core.data.node.ValueNode;
+import io.xpipe.core.data.node.*;
 
 import java.io.IOException;
 import java.io.OutputStream;
@@ -11,12 +8,12 @@ import java.nio.charset.StandardCharsets;
 
 public class GenericDataStreamWriter {
 
-    private static final int TUPLE_ID = 1;
-    private static final int ARRAY_ID = 2;
-    private static final int VALUE_ID = 3;
-    private static final int NAME_ID = 4;
+    public static void writeStructure(OutputStream out, DataStructureNode node) throws IOException {
+        out.write(DataStructureNodeIO.GENERIC_STRUCTURE_ID);
+        write(out, node);
+    }
 
-    public static void write(OutputStream out, DataStructureNode node) throws IOException {
+    private static void write(OutputStream out, DataStructureNode node) throws IOException {
         if (node.isTuple()) {
             writeTuple(out, (TupleNode) node);
         } else if (node.isArray()) {
@@ -29,23 +26,25 @@ public class GenericDataStreamWriter {
     }
 
     private static void writeName(OutputStream out, String s) throws IOException {
-        var b = s.getBytes(StandardCharsets.UTF_8);
-        out.write(NAME_ID);
-        out.write(b.length);
-        out.write(b);
+        if (s != null) {
+            var b = s.getBytes(StandardCharsets.UTF_8);
+            out.write(DataStructureNodeIO.GENERIC_NAME_ID);
+            out.write(b.length);
+            out.write(b);
+        }
     }
 
     private static void writeTuple(OutputStream out, TupleNode tuple) throws IOException {
-        out.write(TUPLE_ID);
+        out.write(DataStructureNodeIO.GENERIC_TUPLE_ID);
         out.write(tuple.size());
         for (int i = 0; i < tuple.size(); i++) {
-            writeName(out, tuple.nameAt(i));
+            writeName(out, tuple.keyNameAt(i));
             write(out, tuple.at(i));
         }
     }
 
     private static void writeArray(OutputStream out, ArrayNode array) throws IOException {
-        out.write(ARRAY_ID);
+        out.write(DataStructureNodeIO.GENERIC_ARRAY_ID);
         out.write(array.size());
         for (int i = 0; i < array.size(); i++) {
             write(out, array.at(i));
@@ -53,7 +52,7 @@ public class GenericDataStreamWriter {
     }
 
     private static void writeValue(OutputStream out, ValueNode value) throws IOException {
-        out.write(VALUE_ID);
+        out.write(DataStructureNodeIO.GENERIC_VALUE_ID);
         out.write(value.getRawData().length);
         out.write(value.getRawData());
     }
diff --git a/core/src/main/java/io/xpipe/core/data/generic/GenericTupleReader.java b/core/src/main/java/io/xpipe/core/data/generic/GenericTupleReader.java
index 933159ed..1ce0df6e 100644
--- a/core/src/main/java/io/xpipe/core/data/generic/GenericTupleReader.java
+++ b/core/src/main/java/io/xpipe/core/data/generic/GenericTupleReader.java
@@ -42,6 +42,11 @@ public class GenericTupleReader implements GenericAbstractReader {
     }
 
     private void putNode(DataStructureNode node) {
+        // If no key was read, assume null key
+        if (this.names.size() == this.nodes.size()) {
+            this.names.add(null);
+        }
+
         this.nodes.add(node);
         currentIndex++;
     }
diff --git a/core/src/main/java/io/xpipe/core/data/node/ArrayNode.java b/core/src/main/java/io/xpipe/core/data/node/ArrayNode.java
index 387ad1b1..748647fa 100644
--- a/core/src/main/java/io/xpipe/core/data/node/ArrayNode.java
+++ b/core/src/main/java/io/xpipe/core/data/node/ArrayNode.java
@@ -1,100 +1,66 @@
 package io.xpipe.core.data.node;
 
 import io.xpipe.core.data.type.ArrayType;
-import lombok.EqualsAndHashCode;
 
-import java.util.*;
-import java.util.function.Consumer;
+import java.util.List;
+import java.util.Objects;
 import java.util.stream.Collectors;
-import java.util.stream.Stream;
 
-@EqualsAndHashCode(callSuper = false)
-public class ArrayNode extends DataStructureNode {
-
-    private final List<DataStructureNode> valueNodes;
-
-    private ArrayNode(List<DataStructureNode> valueNodes) {
-        this.valueNodes = valueNodes;
-    }
+public abstract class ArrayNode extends DataStructureNode {
 
     public static ArrayNode of(DataStructureNode... dsn) {
         return of(List.of(dsn));
     }
 
-    public static ArrayNode of(List<DataStructureNode> valueNodes) {
-        return new ArrayNode(valueNodes);
+    public static ArrayNode of(List<DataStructureNode> nodes) {
+        return new SimpleArrayNode(true, nodes);
     }
 
-    public static ArrayNode copyOf(List<DataStructureNode> valueNodes) {
-        return new ArrayNode(new ArrayList<>(valueNodes));
+    public static ArrayNode of(boolean mutable, List<DataStructureNode> nodes) {
+        return new SimpleArrayNode(mutable, nodes);
+    }
+
+    protected ArrayNode() {
     }
 
     @Override
-    public DataStructureNode put(DataStructureNode node) {
-        valueNodes.add(node);
-        return this;
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof ArrayNode that)) return false;
+        return getNodes().equals(that.getNodes());
     }
 
     @Override
-    public DataStructureNode set(int index, DataStructureNode node) {
-        valueNodes.add(index, node);
-        return this;
+    public int hashCode() {
+        return Objects.hash(getNodes());
     }
 
     @Override
-    public Stream<DataStructureNode> stream() {
-        return Collections.unmodifiableList(valueNodes).stream();
-    }
-
-    @Override
-    public boolean isArray() {
+    public final boolean isArray() {
         return true;
     }
 
     @Override
-    public int size() {
-        return valueNodes.size();
-    }
-
-    @Override
-    protected String getName() {
+    protected final String getName() {
         return "array node";
     }
 
     @Override
-    public String toString(int indent) {
-        var content = valueNodes.stream().map(n -> n.toString(indent)).collect(Collectors.joining(", "));
-        return "[" + content + "]";
+    public abstract ArrayNode immutableView();
+
+    @Override
+    public abstract ArrayNode mutableCopy();
+
+    protected abstract String getIdentifier();
+
+    @Override
+    public final String toString(int indent) {
+        var content = getNodes().stream().map(n -> n.toString(indent)).collect(Collectors.joining(", "));
+        return "(" + getIdentifier() + ") [" + content + "]";
     }
 
     @Override
-    public ArrayType determineDataType() {
-        return ArrayType.ofSharedType(valueNodes.stream().map(DataStructureNode::determineDataType).toList());
-    }
-
-    @Override
-    public DataStructureNode clear() {
-        valueNodes.clear();
-        return this;
-    }
-
-    @Override
-    public DataStructureNode at(int index) {
-        return valueNodes.get(index);
-    }
-
-    @Override
-    public void forEach(Consumer<? super DataStructureNode> action) {
-        valueNodes.forEach(action);
-    }
-
-    @Override
-    public Spliterator<DataStructureNode> spliterator() {
-        return valueNodes.spliterator();
-    }
-
-    @Override
-    public Iterator<DataStructureNode> iterator() {
-        return valueNodes.iterator();
+    public final ArrayType determineDataType() {
+        return ArrayType.ofSharedType(getNodes().stream().map(DataStructureNode::determineDataType).toList());
     }
 }
diff --git a/core/src/main/java/io/xpipe/core/data/node/DataStructureNode.java b/core/src/main/java/io/xpipe/core/data/node/DataStructureNode.java
index 6a864eb9..7a1ab59e 100644
--- a/core/src/main/java/io/xpipe/core/data/node/DataStructureNode.java
+++ b/core/src/main/java/io/xpipe/core/data/node/DataStructureNode.java
@@ -3,6 +3,7 @@ package io.xpipe.core.data.node;
 import io.xpipe.core.data.type.DataType;
 
 import java.util.Iterator;
+import java.util.List;
 import java.util.Optional;
 import java.util.Spliterator;
 import java.util.function.Consumer;
@@ -10,12 +11,37 @@ import java.util.stream.Stream;
 
 public abstract class DataStructureNode implements Iterable<DataStructureNode> {
 
+    public abstract DataStructureNode mutableCopy();
+
+    public String keyNameAt(int index) {
+        throw unsupported("key name at");
+    }
+
+    public List<KeyValue> getKeyValuePairs() {
+        throw unsupported("get key value pairs");
+    }
+
+    public List<String> getKeyNames() {
+        throw unsupported("get key names");
+    }
+
+    public List<DataStructureNode> getNodes() {
+        throw unsupported("get nodes");
+    }
+
+    public record KeyValue(String key, DataStructureNode value) {
+    }
+
     protected abstract String getName();
 
     protected UnsupportedOperationException unsupported(String s) {
         return new UnsupportedOperationException(getName() + " does not support " + s);
     }
 
+    public abstract boolean isMutable();
+
+    public abstract DataStructureNode immutableView();
+
     @Override
     public String toString() {
         return toString(0);
diff --git a/core/src/main/java/io/xpipe/core/data/node/ImmutableValueNode.java b/core/src/main/java/io/xpipe/core/data/node/ImmutableValueNode.java
index 78106da6..cca60e36 100644
--- a/core/src/main/java/io/xpipe/core/data/node/ImmutableValueNode.java
+++ b/core/src/main/java/io/xpipe/core/data/node/ImmutableValueNode.java
@@ -10,7 +10,22 @@ public class ImmutableValueNode extends ValueNode {
 
     @Override
     public String toString(int indent) {
-        return getClass().getSimpleName() + "(" + new String(data) + ")";
+        return new String(data) + "(I)";
+    }
+
+    @Override
+    public boolean isMutable() {
+        return false;
+    }
+
+    @Override
+    public ValueNode immutableView() {
+        return this;
+    }
+
+    @Override
+    public ValueNode mutableCopy() {
+        return ValueNode.mutable(data);
     }
 
     @Override
diff --git a/core/src/main/java/io/xpipe/core/data/node/MutableValueNode.java b/core/src/main/java/io/xpipe/core/data/node/MutableValueNode.java
index f4ccefb1..a100359f 100644
--- a/core/src/main/java/io/xpipe/core/data/node/MutableValueNode.java
+++ b/core/src/main/java/io/xpipe/core/data/node/MutableValueNode.java
@@ -10,7 +10,22 @@ public class MutableValueNode extends ValueNode {
 
     @Override
     public String toString(int indent) {
-        return getClass().getSimpleName() + "(" + new String(data) + ")";
+        return new String(data) + "(M)";
+    }
+
+    @Override
+    public boolean isMutable() {
+        return true;
+    }
+
+    @Override
+    public ValueNode immutableView() {
+        return new ImmutableValueNode(data);
+    }
+
+    @Override
+    public ValueNode mutableCopy() {
+        return new MutableValueNode(data);
     }
 
     @Override
diff --git a/core/src/main/java/io/xpipe/core/data/node/NoKeyTupleNode.java b/core/src/main/java/io/xpipe/core/data/node/NoKeyTupleNode.java
index 7f2ef757..9a4e3a47 100644
--- a/core/src/main/java/io/xpipe/core/data/node/NoKeyTupleNode.java
+++ b/core/src/main/java/io/xpipe/core/data/node/NoKeyTupleNode.java
@@ -3,27 +3,46 @@ package io.xpipe.core.data.node;
 import io.xpipe.core.data.type.DataType;
 import io.xpipe.core.data.type.TupleType;
 
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
-import java.util.Optional;
+import java.util.stream.Collectors;
 
 public class NoKeyTupleNode extends TupleNode {
 
+    private final boolean mutable;
     private final List<DataStructureNode> nodes;
 
-    NoKeyTupleNode(List<DataStructureNode> nodes) {
-        this.nodes = nodes;
+    NoKeyTupleNode(boolean mutable, List<DataStructureNode> nodes) {
+        this.mutable = mutable;
+        this.nodes = mutable ? nodes : Collections.unmodifiableList(nodes);
+    }
+
+    @Override
+    public TupleNode mutableCopy() {
+        return new NoKeyTupleNode(true, nodes.stream()
+                .map(DataStructureNode::mutableCopy)
+                .collect(Collectors.toCollection(ArrayList::new)));
+    }
+
+    @Override
+    public TupleNode immutableView() {
+        return new NoKeyTupleNode(false, nodes.stream()
+                .map(DataStructureNode::immutableView)
+                .collect(Collectors.toCollection(ArrayList::new)));
     }
 
     @Override
     public DataStructureNode set(int index, DataStructureNode node) {
+        checkMutable();
+
         nodes.set(index, node);
         return this;
     }
 
     @Override
     public DataType determineDataType() {
-        return TupleType.of(null, nodes.stream().map(DataStructureNode::determineDataType).toList());
+        return TupleType.of(nodes.stream().map(DataStructureNode::determineDataType).toList());
     }
 
     @Override
@@ -31,40 +50,37 @@ public class NoKeyTupleNode extends TupleNode {
         return "no key tuple node";
     }
 
+    @Override
+    public boolean isMutable() {
+        return mutable;
+    }
+
     @Override
     public DataStructureNode at(int index) {
         return nodes.get(index);
     }
 
-    @Override
-    public DataStructureNode forKey(String name) {
-        throw unsupported("key indexing");
-    }
-
-    @Override
-    public Optional<DataStructureNode> forKeyIfPresent(String name) {
-        return Optional.empty();
-    }
-
     @Override
     public int size() {
         return nodes.size();
     }
 
-    public String nameAt(int index) {
-        throw unsupported("name getter");
-    }
-
     @Override
     public List<KeyValue> getKeyValuePairs() {
         return nodes.stream().map(n -> new KeyValue(null, n)).toList();
     }
 
-    public List<String> getNames() {
+    @Override
+    public List<String> getKeyNames() {
         return Collections.nCopies(size(), null);
     }
 
     public List<DataStructureNode> getNodes() {
-        return Collections.unmodifiableList(nodes);
+        return nodes;
+    }
+
+    @Override
+    protected String getIdentifier() {
+        return "NK";
     }
 }
diff --git a/core/src/main/java/io/xpipe/core/data/node/SimpleArrayNode.java b/core/src/main/java/io/xpipe/core/data/node/SimpleArrayNode.java
new file mode 100644
index 00000000..950af038
--- /dev/null
+++ b/core/src/main/java/io/xpipe/core/data/node/SimpleArrayNode.java
@@ -0,0 +1,114 @@
+package io.xpipe.core.data.node;
+
+import java.util.*;
+import java.util.function.Consumer;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class SimpleArrayNode extends ArrayNode {
+
+    private final boolean mutable;
+    private final List<DataStructureNode> nodes;
+
+    SimpleArrayNode(boolean mutable, List<DataStructureNode> nodes) {
+        this.nodes = nodes;
+        this.mutable = mutable;
+    }
+
+    private void checkMutable() {
+        if (!mutable) {
+            throw new UnsupportedOperationException("Array node is immutable");
+        }
+    }
+
+    @Override
+    public DataStructureNode put(DataStructureNode node) {
+        checkMutable();
+
+        nodes.add(node);
+        return this;
+    }
+
+    @Override
+    public DataStructureNode set(int index, DataStructureNode node) {
+        checkMutable();
+
+        nodes.add(index, node);
+        return this;
+    }
+
+    @Override
+    public Stream<DataStructureNode> stream() {
+        return nodes.stream();
+    }
+
+    @Override
+    public int size() {
+        return nodes.size();
+    }
+
+    @Override
+    public ArrayNode mutableCopy() {
+        return new SimpleArrayNode(true, nodes.stream()
+                .map(DataStructureNode::mutableCopy)
+                .collect(Collectors.toCollection(ArrayList::new)));
+    }
+
+    @Override
+    protected String getIdentifier() {
+        return "S";
+    }
+
+    @Override
+    public boolean isMutable() {
+        return mutable;
+    }
+
+    @Override
+    public ArrayNode immutableView() {
+        return new SimpleArrayNode(false, nodes.stream()
+                .map(DataStructureNode::immutableView)
+                .collect(Collectors.toCollection(ArrayList::new)));
+    }
+
+    @Override
+    public DataStructureNode clear() {
+        checkMutable();
+
+        nodes.clear();
+        return this;
+    }
+
+    @Override
+    public DataStructureNode at(int index) {
+        return nodes.get(index);
+    }
+
+    @Override
+    public void forEach(Consumer<? super DataStructureNode> action) {
+        nodes.forEach(action);
+    }
+
+    @Override
+    public Spliterator<DataStructureNode> spliterator() {
+        return nodes.spliterator();
+    }
+
+    @Override
+    public Iterator<DataStructureNode> iterator() {
+        return nodes.iterator();
+    }
+
+    @Override
+    public List<DataStructureNode> getNodes() {
+        return nodes;
+    }
+
+    @Override
+    public DataStructureNode remove(int index) {
+        checkMutable();
+
+        nodes.remove(index);
+        return this;
+    }
+}
diff --git a/core/src/main/java/io/xpipe/core/data/node/SimpleTupleNode.java b/core/src/main/java/io/xpipe/core/data/node/SimpleTupleNode.java
index ee0fdf28..d2b80091 100644
--- a/core/src/main/java/io/xpipe/core/data/node/SimpleTupleNode.java
+++ b/core/src/main/java/io/xpipe/core/data/node/SimpleTupleNode.java
@@ -2,26 +2,42 @@ package io.xpipe.core.data.node;
 
 import io.xpipe.core.data.type.DataType;
 import io.xpipe.core.data.type.TupleType;
-import lombok.EqualsAndHashCode;
 
-import java.util.ArrayList;
-import java.util.Collections;
-import java.util.List;
-import java.util.Optional;
+import java.util.*;
+import java.util.stream.Collectors;
 
-@EqualsAndHashCode(callSuper = false)
 public class SimpleTupleNode extends TupleNode {
 
+    private final boolean mutable;
     private final List<String> names;
     private final List<DataStructureNode> nodes;
 
-    SimpleTupleNode(List<String> names, List<DataStructureNode> nodes) {
-        this.names = names;
-        this.nodes = nodes;
+    SimpleTupleNode(boolean mutable, List<String> names, List<DataStructureNode> nodes) {
+        this.mutable = mutable;
+        this.names = mutable ? names : Collections.unmodifiableList(names);
+        this.nodes = mutable ? nodes : Collections.unmodifiableList(nodes);
+    }
+
+    @Override
+    public TupleNode mutableCopy() {
+        var nodesCopy = nodes.stream()
+                .map(DataStructureNode::mutableCopy)
+                .collect(Collectors.toCollection(ArrayList::new));
+        return new SimpleTupleNode(true, new ArrayList<>(names), nodesCopy);
+    }
+
+    @Override
+    public TupleNode immutableView() {
+        var nodesCopy = nodes.stream()
+                .map(DataStructureNode::immutableView)
+                .collect(Collectors.toCollection(ArrayList::new));
+        return new SimpleTupleNode(false, names, nodesCopy);
     }
 
     @Override
     public DataStructureNode set(int index, DataStructureNode node) {
+        checkMutable();
+
         nodes.set(index, node);
         return this;
     }
@@ -36,6 +52,11 @@ public class SimpleTupleNode extends TupleNode {
         return "tuple node";
     }
 
+    @Override
+    public boolean isMutable() {
+        return mutable;
+    }
+
     @Override
     public DataStructureNode at(int index) {
         return nodes.get(index);
@@ -57,6 +78,8 @@ public class SimpleTupleNode extends TupleNode {
 
     @Override
     public DataStructureNode clear() {
+        checkMutable();
+
         nodes.clear();
         names.clear();
         return this;
@@ -68,7 +91,7 @@ public class SimpleTupleNode extends TupleNode {
         return nodes.size();
     }
 
-    public String nameAt(int index) {
+    public String keyNameAt(int index) {
         return names.get(index);
     }
 
@@ -76,16 +99,21 @@ public class SimpleTupleNode extends TupleNode {
     public List<KeyValue> getKeyValuePairs() {
         var l = new ArrayList<KeyValue>(size());
         for (int i = 0; i < size(); i++) {
-            l.add(new KeyValue(getNames().get(i), getNodes().get(i)));
+            l.add(new KeyValue(getKeyNames().get(i), getNodes().get(i)));
         }
         return l;
     }
 
-    public List<String> getNames() {
+    public List<String> getKeyNames() {
         return Collections.unmodifiableList(names);
     }
 
     public List<DataStructureNode> getNodes() {
         return Collections.unmodifiableList(nodes);
     }
+
+    @Override
+    protected String getIdentifier() {
+        return "S";
+    }
 }
diff --git a/core/src/main/java/io/xpipe/core/data/node/TupleNode.java b/core/src/main/java/io/xpipe/core/data/node/TupleNode.java
index 69b9515e..14c44fdd 100644
--- a/core/src/main/java/io/xpipe/core/data/node/TupleNode.java
+++ b/core/src/main/java/io/xpipe/core/data/node/TupleNode.java
@@ -1,7 +1,5 @@
 package io.xpipe.core.data.node;
 
-import lombok.Value;
-
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
@@ -18,11 +16,7 @@ public abstract class TupleNode extends DataStructureNode {
             throw new IllegalArgumentException("Nodes must be not null");
         }
 
-        return new NoKeyTupleNode(nodes);
-    }
-
-    public static TupleNode copyOf(List<DataStructureNode> nodes) {
-        return TupleNode.of(List.copyOf(nodes));
+        return new NoKeyTupleNode(true, nodes);
     }
 
     public static TupleNode of(List<String> names, List<DataStructureNode> nodes) {
@@ -36,55 +30,62 @@ public abstract class TupleNode extends DataStructureNode {
             throw new IllegalArgumentException("Names and nodes must have the same length");
         }
 
-        return new SimpleTupleNode(names, nodes);
+        return new SimpleTupleNode(true, names, nodes);
     }
 
-    public static TupleNode ofRaw(List<String> names, List<DataStructureNode> nodes) {
+    public static TupleNode of(boolean mutable, List<String> names, List<DataStructureNode> nodes) {
         if (names == null) {
             throw new IllegalArgumentException("Names must be not null");
         }
         if (nodes == null) {
             throw new IllegalArgumentException("Nodes must be not null");
         }
-        return new SimpleTupleNode(names, nodes);
-    }
-
-    public static TupleNode copyOf(List<String> names, List<DataStructureNode> nodes) {
-        return TupleNode.of(List.copyOf(names), List.copyOf(nodes));
+        return new SimpleTupleNode(mutable, names, nodes);
     }
 
     public final boolean isTuple() {
         return true;
     }
 
+    protected abstract String getIdentifier();
+
+    protected void checkMutable() {
+        if (!isMutable()) {
+            throw new UnsupportedOperationException("Tuple node is immutable");
+        }
+    }
+
+    @Override
+    public abstract TupleNode mutableCopy();
+
+    @Override
+    public abstract TupleNode immutableView();
+
     @Override
     public String toString(int indent) {
         var is = " ".repeat(indent);
-        var start = getClass().getSimpleName() + " {\n";
+        var start = "(" + getIdentifier() + ") {\n";
         var kvs = getKeyValuePairs().stream().map(kv -> {
-            if (kv.key == null) {
-                return is + " " + kv.value.toString(indent + 1) + "\n";
+            if (kv.key() == null) {
+                return is + " " + kv.value().toString(indent + 1) + "\n";
             } else {
-                return is + " " + kv.key + "=" + kv.value.toString(indent + 1) + "\n";
+                return is + " " + kv.key() + "=" + kv.value().toString(indent + 1) + "\n";
             }
         }).collect(Collectors.joining());
         var end = is + "}";
         return start + kvs + end;
     }
 
-    public abstract String nameAt(int index);
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof TupleNode that)) return false;
+        return getKeyNames().equals(that.getKeyNames()) && getNodes().equals(that.getNodes());
+    }
 
-    public abstract List<KeyValue> getKeyValuePairs();
-
-    public abstract List<String> getNames();
-
-    public abstract List<DataStructureNode> getNodes();
-
-    @Value
-    public static class KeyValue {
-
-        String key;
-        DataStructureNode value;
+    @Override
+    public int hashCode() {
+        return Objects.hash(getKeyNames(), getNodes());
     }
 
     public static class Builder {
@@ -104,11 +105,11 @@ public abstract class TupleNode extends DataStructureNode {
         }
 
         public TupleNode build() {
-            boolean hasKeys = entries.stream().anyMatch(kv -> kv.key != null);
+            boolean hasKeys = entries.stream().anyMatch(kv -> kv.key() != null);
             return hasKeys ? TupleNode.of(
-                    entries.stream().map(kv -> kv.key).toList(),
-                    entries.stream().map(kv -> kv.value).toList()) :
-                    TupleNode.of(entries.stream().map(kv -> kv.value).toList());
+                    entries.stream().map(KeyValue::key).toList(),
+                    entries.stream().map(KeyValue::value).toList()) :
+                    TupleNode.of(entries.stream().map(KeyValue::value).toList());
         }
     }
 }
diff --git a/core/src/main/java/io/xpipe/core/data/node/ValueNode.java b/core/src/main/java/io/xpipe/core/data/node/ValueNode.java
index f46a0e4e..ae3cdc67 100644
--- a/core/src/main/java/io/xpipe/core/data/node/ValueNode.java
+++ b/core/src/main/java/io/xpipe/core/data/node/ValueNode.java
@@ -2,11 +2,10 @@ package io.xpipe.core.data.node;
 
 import io.xpipe.core.data.type.DataType;
 import io.xpipe.core.data.type.ValueType;
-import lombok.EqualsAndHashCode;
 
 import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
 
-@EqualsAndHashCode(callSuper = false)
 public abstract class ValueNode extends DataStructureNode {
 
     private static final byte[] NULL = new byte[]{0};
@@ -14,6 +13,24 @@ public abstract class ValueNode extends DataStructureNode {
     protected ValueNode() {
     }
 
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (!(o instanceof ValueNode that)) return false;
+        return Arrays.equals(getRawData(), that.getRawData());
+    }
+
+    @Override
+    public int hashCode() {
+        return Arrays.hashCode(getRawData());
+    }
+
+    @Override
+    public abstract ValueNode immutableView();
+
+    @Override
+    public abstract ValueNode mutableCopy();
+
     public static ValueNode immutable(byte[] data) {
         return new ImmutableValueNode(data);
     }
diff --git a/core/src/main/java/io/xpipe/core/data/type/DataTypeVisitors.java b/core/src/main/java/io/xpipe/core/data/type/DataTypeVisitors.java
index 3fd10503..9525fac8 100644
--- a/core/src/main/java/io/xpipe/core/data/type/DataTypeVisitors.java
+++ b/core/src/main/java/io/xpipe/core/data/type/DataTypeVisitors.java
@@ -27,6 +27,7 @@ public class DataTypeVisitors {
             @Override
             public void onArray(ArrayType type) {
                 typeConsumer.accept(type);
+                typeConsumer.accept(type.getSharedType());
             }
 
             @Override
diff --git a/core/src/main/java/io/xpipe/core/data/type/TupleType.java b/core/src/main/java/io/xpipe/core/data/type/TupleType.java
index f5f463a3..a7192c6d 100644
--- a/core/src/main/java/io/xpipe/core/data/type/TupleType.java
+++ b/core/src/main/java/io/xpipe/core/data/type/TupleType.java
@@ -68,11 +68,11 @@ public class TupleType extends DataType {
 
         int counter = 0;
         for (var kv : t.getKeyValuePairs()) {
-            if (!Objects.equals(kv.getKey(), names.get(counter))) {
+            if (!Objects.equals(kv.key(), names.get(counter))) {
                 return false;
             }
 
-            if (!types.get(counter).matches(kv.getValue())) {
+            if (!types.get(counter).matches(kv.value())) {
                 return false;
             }
             counter++;
diff --git a/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamCallback.java b/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamCallback.java
index d8ac716c..f1e9b68d 100644
--- a/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamCallback.java
+++ b/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamCallback.java
@@ -3,8 +3,6 @@ package io.xpipe.core.data.typed;
 import io.xpipe.core.data.node.DataStructureNode;
 import io.xpipe.core.data.type.TupleType;
 
-import java.io.IOException;
-
 public interface TypedDataStreamCallback {
 
     default void onValue(byte[] data) {
@@ -19,7 +17,7 @@ public interface TypedDataStreamCallback {
     default void onTupleEnd() {
     }
 
-    default void onArrayBegin(int size) throws IOException {
+    default void onArrayBegin(int size) {
     }
 
     default void onArrayEnd() {
diff --git a/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamParser.java b/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamParser.java
index e84c0f5e..54c07b63 100644
--- a/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamParser.java
+++ b/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamParser.java
@@ -90,9 +90,16 @@ public class TypedDataStreamParser {
 
                 parseValue(in, cb);
             }
+            case DataStructureNodeIO.GENERIC_STRUCTURE_ID -> {
+                if (!type.isWildcard()) {
+                    throw new IllegalStateException("Got structure but expected " + type.getName());
+                }
+
+                GenericDataStreamParser.parse(in, getGenericReader());
+                cb.onGenericNode(getGenericReader().create());
+            }
             default -> {
-                GenericDataStreamParser.
-                throw new IllegalStateException("Unexpected value: " + b);
+                throw new IllegalStateException("Unexpected type id: " + b);
             }
         }
     }
@@ -100,14 +107,7 @@ public class TypedDataStreamParser {
     private void parseTypedTuple(InputStream in, TypedDataStreamCallback cb, TupleType type) throws IOException {
         cb.onTupleBegin(type);
         for (int i = 0; i < type.getSize(); i++) {
-            if (type.getTypes().get(i).isWildcard()) {
-                var r = getGenericReader();
-                GenericDataStreamParser.read(in, r);
-                var node = r.create();
-                cb.onGenericNode(node);
-            } else {
-                parse(in, cb, type.getTypes().get(i));
-            }
+            parse(in, cb, type.getTypes().get(i));
         }
         cb.onTupleEnd();
     }
@@ -123,14 +123,7 @@ public class TypedDataStreamParser {
         var size = in.read();
         cb.onArrayBegin(size);
         for (int i = 0; i < size; i++) {
-            if (type.getSharedType().isWildcard()) {
-                var r = getGenericReader();
-                GenericDataStreamParser.read(in, r);
-                var node = r.create();
-                cb.onGenericNode(node);
-            } else {
-                parse(in, cb, type.getSharedType());
-            }
+            parse(in, cb, type.getSharedType());
         }
         cb.onArrayEnd();
     }
diff --git a/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamWriter.java b/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamWriter.java
index 1bbd126e..0a143375 100644
--- a/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamWriter.java
+++ b/core/src/main/java/io/xpipe/core/data/typed/TypedDataStreamWriter.java
@@ -28,7 +28,7 @@ public class TypedDataStreamWriter {
         } else if (node.isValue() && type.isValue()) {
             writeValue(out, (ValueNode) node);
         } else if (type.isWildcard()) {
-            GenericDataStreamWriter.write(out, node);
+            GenericDataStreamWriter.writeStructure(out, node);
         } else {
             throw new IllegalStateException("Incompatible node and type");
         }
diff --git a/core/src/main/java/io/xpipe/core/data/typed/TypedDataStructureNodeReader.java b/core/src/main/java/io/xpipe/core/data/typed/TypedDataStructureNodeReader.java
index a914c899..2c8abd4d 100644
--- a/core/src/main/java/io/xpipe/core/data/typed/TypedDataStructureNodeReader.java
+++ b/core/src/main/java/io/xpipe/core/data/typed/TypedDataStructureNodeReader.java
@@ -1,15 +1,10 @@
 package io.xpipe.core.data.typed;
 
-import io.xpipe.core.data.node.DataStructureNode;
-import io.xpipe.core.data.node.ArrayNode;
-import io.xpipe.core.data.node.SimpleTupleNode;
-import io.xpipe.core.data.node.TupleNode;
-import io.xpipe.core.data.node.ValueNode;
+import io.xpipe.core.data.node.*;
 import io.xpipe.core.data.type.DataType;
-import io.xpipe.core.data.type.TupleType;
 import io.xpipe.core.data.type.DataTypeVisitors;
+import io.xpipe.core.data.type.TupleType;
 
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
@@ -17,22 +12,6 @@ import java.util.Stack;
 
 public class TypedDataStructureNodeReader implements TypedAbstractReader {
 
-    private final List<DataType> flattened;
-    private final Stack<List<DataStructureNode>> children;
-    private final Stack<DataStructureNode> nodes;
-    private final boolean makeImmutable;
-    private int currentDataTypeIndex;
-    private DataStructureNode readNode;
-    private boolean initialized;
-    private int arrayDepth;
-    private TypedDataStructureNodeReader(DataType type, boolean makeImmutable) {
-        flattened = new ArrayList<>();
-        children = new Stack<>();
-        nodes = new Stack<>();
-        type.visit(DataTypeVisitors.flatten(d -> flattened.add(d)));
-        this.makeImmutable = makeImmutable;
-    }
-
     public static TypedDataStructureNodeReader mutable(DataType type) {
         return new TypedDataStructureNodeReader(type, false);
     }
@@ -41,10 +20,30 @@ public class TypedDataStructureNodeReader implements TypedAbstractReader {
         return new TypedDataStructureNodeReader(type, true);
     }
 
+    private final boolean makeImmutable;
+    private DataStructureNode readNode;
+
+    private final Stack<List<DataStructureNode>> children;
+    private final Stack<DataStructureNode> nodes;
+    private int arrayDepth;
+
+    private final List<DataType> flattened;
+    private DataType expectedType;
+    private int currentExpectedTypeIndex;
+
+    private TypedDataStructureNodeReader(DataType type, boolean makeImmutable) {
+        flattened = new ArrayList<>();
+        type.visit(DataTypeVisitors.flatten(flattened::add));
+        children = new Stack<>();
+        nodes = new Stack<>();
+        this.makeImmutable = makeImmutable;
+        expectedType = flattened.get(0);
+    }
+
     @Override
     public void onNodeBegin() {
         if (nodes.size() != 0 || children.size() != 0) {
-            throw new IllegalStateException();
+            throw new IllegalStateException("Reader did not completely reset");
         }
 
         readNode = null;
@@ -56,30 +55,37 @@ public class TypedDataStructureNodeReader implements TypedAbstractReader {
     }
 
     public DataStructureNode create() {
+        if (readNode == null) {
+            throw new IllegalStateException("Reader is not finished yet");
+        }
+
         return readNode;
     }
 
     @Override
     public void onNodeEnd() {
         if (nodes.size() != 0 || children.size() != 0 || readNode == null) {
-            throw new IllegalStateException();
+            throw new IllegalStateException("Reader is not finished yet");
         }
+    }
 
-        initialized = false;
+    private void finishNode(DataStructureNode node) {
+        if (nodes.empty()) {
+            readNode = node;
+        } else {
+            children.peek().add(node);
+        }
     }
 
     @Override
     public void onValue(byte[] data) {
-        var val = makeImmutable ? ValueNode.immutable(data) : ValueNode.mutable(data);
-        if (!initialized) {
-            readNode = val;
-            return;
+        if (!expectedType.isValue()) {
+            throw new IllegalStateException("Expected " + expectedType.getName() + " but got value");
         }
 
-        children.peek().add(val);
-        if (!flattened.get(currentDataTypeIndex).isArray()) {
-            currentDataTypeIndex++;
-        }
+        var val = makeImmutable ? ValueNode.immutable(data) : ValueNode.mutable(data);
+        finishNode(val);
+        moveExpectedType(false);
     }
 
     private boolean isInArray() {
@@ -88,25 +94,22 @@ public class TypedDataStructureNodeReader implements TypedAbstractReader {
 
     @Override
     public void onGenericNode(DataStructureNode node) {
-        children.peek().add(node);
-        if (!isInArray()) {
-            currentDataTypeIndex++;
+        if (!expectedType.isWildcard()) {
+            throw new IllegalStateException("Expected " + expectedType.getName() + " but got generic node");
         }
+
+        finishNode(makeImmutable ? node.immutableView() : node);
+        moveExpectedType(false);
     }
 
     @Override
     public void onTupleBegin(TupleType type) {
-        if (!isInArray() && !flattened.get(currentDataTypeIndex).isTuple()) {
-            throw new IllegalStateException();
+        if (!expectedType.isTuple()) {
+            throw new IllegalStateException("Expected " + expectedType.getName() + " but got tuple");
         }
 
-        TupleType tupleType = (TupleType) flattened.get(currentDataTypeIndex);
-        if (!initialized || !flattened.get(currentDataTypeIndex).isArray()) {
-            currentDataTypeIndex++;
-        }
-        if (!initialized) {
-            initialized = true;
-        }
+        TupleType tupleType = expectedType.asTuple();
+        moveExpectedType(false);
 
         var l = new ArrayList<DataStructureNode>(tupleType.getSize());
         children.push(l);
@@ -114,7 +117,7 @@ public class TypedDataStructureNodeReader implements TypedAbstractReader {
         var tupleNames = makeImmutable ?
                 Collections.unmodifiableList(tupleType.getNames()) : new ArrayList<>(tupleType.getNames());
         var tupleNodes = makeImmutable ? Collections.unmodifiableList(l) : l;
-        var newNode = TupleNode.ofRaw(tupleNames, tupleNodes);
+        var newNode = TupleNode.of(!makeImmutable, tupleNames, tupleNodes);
         nodes.push(newNode);
     }
 
@@ -123,49 +126,52 @@ public class TypedDataStructureNodeReader implements TypedAbstractReader {
         children.pop();
         var popped = nodes.pop();
         if (!popped.isTuple()) {
-            throw new IllegalStateException();
+            throw new IllegalStateException("No tuple to end");
         }
 
-        SimpleTupleNode tuple = (SimpleTupleNode) popped;
-        if (tuple.getNames().size() != tuple.getNodes().size()) {
-            throw new IllegalStateException("");
+        TupleNode tuple = popped.asTuple();
+        if (tuple.getKeyNames().size() != tuple.getNodes().size()) {
+            throw new IllegalStateException("Tuple node size mismatch");
         }
 
-        if (nodes.empty()) {
-            readNode = popped;
-        } else {
-            children.peek().add(popped);
+        finishNode(popped);
+    }
+
+    private void moveExpectedType(boolean force) {
+        if (!isInArray() || force) {
+            currentExpectedTypeIndex++;
+            expectedType = currentExpectedTypeIndex == flattened.size() ? null : flattened.get(currentExpectedTypeIndex);
         }
     }
 
     @Override
-    public void onArrayBegin(int size) throws IOException {
-        if (!flattened.get(currentDataTypeIndex).isArray()) {
-            throw new IllegalStateException();
+    public void onArrayBegin(int size) {
+        if (!expectedType.isArray()) {
+            throw new IllegalStateException("Expected " + expectedType.getName() + " but got array");
         }
 
+        arrayDepth++;
+        moveExpectedType(true);
+
         var l = new ArrayList<DataStructureNode>();
         children.push(l);
 
         var arrayNodes = makeImmutable ? Collections.unmodifiableList(l) : l;
         var newNode = ArrayNode.of(arrayNodes);
         nodes.push(newNode);
-        arrayDepth++;
     }
 
     @Override
     public void onArrayEnd() {
-        arrayDepth--;
         if (!isInArray()) {
-            currentDataTypeIndex++;
+            throw new IllegalStateException("No array to end");
         }
 
+        arrayDepth--;
+        moveExpectedType(true);
+
         children.pop();
         var popped = nodes.pop();
-        if (nodes.empty()) {
-            readNode = popped;
-        } else {
-            children.peek().add(popped);
-        }
+        finishNode(popped);
     }
 }
diff --git a/core/src/main/java/io/xpipe/core/data/typed/TypedReusableDataStructureNodeReader.java b/core/src/main/java/io/xpipe/core/data/typed/TypedReusableDataStructureNodeReader.java
index 2fbccaf6..065cdad7 100644
--- a/core/src/main/java/io/xpipe/core/data/typed/TypedReusableDataStructureNodeReader.java
+++ b/core/src/main/java/io/xpipe/core/data/typed/TypedReusableDataStructureNodeReader.java
@@ -3,10 +3,9 @@ package io.xpipe.core.data.typed;
 import io.xpipe.core.data.node.DataStructureNode;
 import io.xpipe.core.data.node.ValueNode;
 import io.xpipe.core.data.type.DataType;
-import io.xpipe.core.data.type.TupleType;
 import io.xpipe.core.data.type.DataTypeVisitors;
+import io.xpipe.core.data.type.TupleType;
 
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Stack;
@@ -43,7 +42,6 @@ public class TypedReusableDataStructureNodeReader implements TypedAbstractReader
         return arrayDepth >= 1;
     }
 
-
     private boolean initialized() {
         return node != null;
     }
@@ -73,13 +71,25 @@ public class TypedReusableDataStructureNodeReader implements TypedAbstractReader
             return;
         }
 
-        getCurrentParent().set(indices.peek(), node);
+        if (hasParent()) {
+            getCurrentParent().set(indices.peek(), node);
+        } else {
+            this.node = node;
+        }
         if (!indices.isEmpty()) {
             indices.push(indices.pop() + 1);
         }
     }
 
+    private boolean hasParent() {
+        return indices.size() > 0;
+    }
+
     private DataStructureNode getCurrentParent() {
+        if (!hasParent()) {
+            throw new IllegalStateException("No parent available");
+        }
+
         var current = node;
         for (var index : indices.subList(0, indices.size() - 1)) {
             current = current.at(index);
@@ -95,15 +105,6 @@ public class TypedReusableDataStructureNodeReader implements TypedAbstractReader
         return current;
     }
 
-    private void setValue(byte[] data) {
-        var current = node;
-        for (var index : indices) {
-            current = current.at(index);
-        }
-        var value = (ValueNode) current;
-        value.setRawData(data);
-    }
-
     @Override
     public void onTupleBegin(TupleType type) {
         if (!initialized()) {
@@ -128,7 +129,7 @@ public class TypedReusableDataStructureNodeReader implements TypedAbstractReader
     }
 
     @Override
-    public void onArrayBegin(int size) throws IOException {
+    public void onArrayBegin(int size) {
         if (!initialized()) {
             initialReader.onArrayBegin(size);
             return;
@@ -157,7 +158,6 @@ public class TypedReusableDataStructureNodeReader implements TypedAbstractReader
     public void onNodeBegin() {
         if (!initialized()) {
             initialReader.onNodeBegin();
-            return;
         }
     }
 
diff --git a/core/src/test/java/io/xpipe/core/test/DataStructureTest.java b/core/src/test/java/io/xpipe/core/test/DataStructureTest.java
index 6a2938b5..07451d76 100644
--- a/core/src/test/java/io/xpipe/core/test/DataStructureTest.java
+++ b/core/src/test/java/io/xpipe/core/test/DataStructureTest.java
@@ -79,10 +79,10 @@ public class DataStructureTest {
     public void testGenericIo(DataStructureTests.TypedDataset ds) throws IOException {
         for (var el : ds.nodes) {
             var dataOut = new ByteArrayOutputStream();
-            GenericDataStreamWriter.write(dataOut, el);
+            GenericDataStreamWriter.writeStructure(dataOut, el);
             var data = dataOut.toByteArray();
             var reader = new GenericDataStructureNodeReader();
-            GenericDataStreamParser.read(new ByteArrayInputStream(data), reader);
+            GenericDataStreamParser.parse(new ByteArrayInputStream(data), reader);
             var readNode = reader.create();
 
             Assertions.assertEquals(el, readNode);
diff --git a/core/src/test/java/io/xpipe/core/test/DataStructureTests.java b/core/src/test/java/io/xpipe/core/test/DataStructureTests.java
index 751f3b8b..a74c5a79 100644
--- a/core/src/test/java/io/xpipe/core/test/DataStructureTests.java
+++ b/core/src/test/java/io/xpipe/core/test/DataStructureTests.java
@@ -8,6 +8,7 @@ import io.xpipe.core.data.type.*;
 import lombok.AllArgsConstructor;
 
 import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
 import java.util.List;
 
 public class DataStructureTests {
@@ -144,7 +145,7 @@ public class DataStructureTests {
         var val = ValueNode.of("value".getBytes(StandardCharsets.UTF_8));
         var array = ArrayNode.of(List.of(val, ValueNode.nullValue()));
         var tuple = TupleNode.builder()
-                .add("key1", val).add("key2", array).build();
+                .add(val).add("key2", array).build();
         return tuple;
     }
 
@@ -153,12 +154,15 @@ public class DataStructureTests {
         var flatTuple = TupleNode.builder().add("key1", val).build();
 
         var tuple = TupleNode.builder()
-                .add("key1", flatTuple).add("key2", val).build();
+                .add(flatTuple).add("key2", val).build();
         return tuple;
     }
 
     public static DataType createTestDataType6() {
-        return TupleType.of(List.of("key1", "key2"), List.of(WildcardType.of(), WildcardType.of()));
+        var keys = new ArrayList<String>();
+        keys.add(null);
+        keys.add("key2");
+        return TupleType.of(keys, List.of(WildcardType.of(), WildcardType.of()));
     }
 
     public static DataStructureNode createTestData71() {