diff --git a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/add.kt b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/add.kt
index 050d8a7499..f0f8ae06e0 100644
--- a/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/add.kt
+++ b/core/src/main/kotlin/org/jetbrains/kotlinx/dataframe/api/add.kt
@@ -248,6 +248,8 @@ public fun <T> DataFrame<T>.add(body: AddDsl<T>.() -> Unit): DataFrame<T> {
     return dataFrameOf(this@add.columns() + dsl.columns).cast()
 }
 
+@Refine
+@Interpretable("GroupByAdd")
 public inline fun <reified R, T, G> GroupBy<T, G>.add(
     name: String,
     infer: Infer = Infer.Nulls,
diff --git a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/extensions/FunctionCallTransformer.kt b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/extensions/FunctionCallTransformer.kt
index 7668541839..25bd79c5f5 100644
--- a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/extensions/FunctionCallTransformer.kt
+++ b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/extensions/FunctionCallTransformer.kt
@@ -239,8 +239,8 @@ class FunctionCallTransformer(
             val groupMarker = rootMarkers[1]
 
             val (keySchema, groupSchema) = if (groupBy != null) {
-                val keySchema = createPluginDataFrameSchema(groupBy.keys, groupBy.moveToTop)
-                val groupSchema = PluginDataFrameSchema(groupBy.df.columns())
+                val keySchema = groupBy.keys
+                val groupSchema = groupBy.groups
                 keySchema to groupSchema
             } else {
                 PluginDataFrameSchema.EMPTY to PluginDataFrameSchema.EMPTY
diff --git a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/ExpectedArgumentDelegates.kt b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/ExpectedArgumentDelegates.kt
index 2fcc616f92..4bb4f4c7bf 100644
--- a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/ExpectedArgumentDelegates.kt
+++ b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/ExpectedArgumentDelegates.kt
@@ -1,6 +1,7 @@
 package org.jetbrains.kotlinx.dataframe.plugin.impl
 
 import org.jetbrains.kotlinx.dataframe.plugin.impl.AbstractInterpreter.*
+import org.jetbrains.kotlinx.dataframe.plugin.impl.api.GroupBy
 import org.jetbrains.kotlinx.dataframe.plugin.impl.api.TypeApproximation
 import org.jetbrains.kotlinx.dataframe.plugin.impl.data.DataFrameCallableId
 import kotlin.properties.PropertyDelegateProvider
@@ -35,3 +36,7 @@ internal fun <T> AbstractInterpreter<T>.ignore(
 ): ExpectedArgumentProvider<Nothing?> =
     arg(name, lens = Interpreter.Id, defaultValue = Present(null))
 
+internal fun <T> AbstractInterpreter<T>.groupBy(
+    name: ArgumentName? = null
+): ExpectedArgumentProvider<GroupBy> = arg(name, lens = Interpreter.GroupBy)
+
diff --git a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/Interpreter.kt b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/Interpreter.kt
index d47473f76f..239147caa6 100644
--- a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/Interpreter.kt
+++ b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/Interpreter.kt
@@ -26,6 +26,8 @@ interface Interpreter<T> {
 
     data object Schema : Lens
 
+    data object GroupBy : Lens
+
     data object  Id : Lens
 
     // required to compute whether resulting schema should be inheritor of previous class or a new class
diff --git a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/SimpleCol.kt b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/SimpleCol.kt
index 06551c1cf1..5a88dee41e 100644
--- a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/SimpleCol.kt
+++ b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/SimpleCol.kt
@@ -27,6 +27,10 @@ data class PluginDataFrameSchema(
     }
 }
 
+fun PluginDataFrameSchema.add(name: String, type: ConeKotlinType, context: KotlinTypeFacade): PluginDataFrameSchema {
+    return PluginDataFrameSchema(columns() + context.simpleColumnOf(name, type))
+}
+
 private fun List<SimpleCol>.asString(indent: String = ""): String {
     return joinToString("\n") {
         val col = when (it) {
diff --git a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/groupBy.kt b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/groupBy.kt
index 8ce8a8c696..0cdef0c63a 100644
--- a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/groupBy.kt
+++ b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/impl/api/groupBy.kt
@@ -19,11 +19,14 @@ import org.jetbrains.kotlinx.dataframe.plugin.impl.Present
 import org.jetbrains.kotlinx.dataframe.plugin.impl.SimpleCol
 import org.jetbrains.kotlinx.dataframe.plugin.impl.SimpleColumnGroup
 import org.jetbrains.kotlinx.dataframe.plugin.impl.SimpleFrameColumn
+import org.jetbrains.kotlinx.dataframe.plugin.impl.add
 import org.jetbrains.kotlinx.dataframe.plugin.impl.data.ColumnWithPathApproximation
 import org.jetbrains.kotlinx.dataframe.plugin.impl.dataFrame
+import org.jetbrains.kotlinx.dataframe.plugin.impl.groupBy
 import org.jetbrains.kotlinx.dataframe.plugin.impl.simpleColumnOf
+import org.jetbrains.kotlinx.dataframe.plugin.impl.type
 
-class GroupBy(val df: PluginDataFrameSchema, val keys: List<ColumnWithPathApproximation>, val moveToTop: Boolean)
+class GroupBy(val keys: PluginDataFrameSchema, val groups: PluginDataFrameSchema)
 
 class DataFrameGroupBy : AbstractInterpreter<GroupBy>() {
     val Arguments.receiver: PluginDataFrameSchema by dataFrame()
@@ -31,7 +34,7 @@ class DataFrameGroupBy : AbstractInterpreter<GroupBy>() {
     val Arguments.cols: ColumnsResolver by arg()
 
     override fun Arguments.interpret(): GroupBy {
-        return GroupBy(receiver, cols.resolve(receiver), moveToTop)
+        return GroupBy(keys = createPluginDataFrameSchema(cols.resolve(receiver), moveToTop), groups = receiver)
     }
 }
 
@@ -52,7 +55,7 @@ class GroupByInto : AbstractInterpreter<Unit>() {
 }
 
 class Aggregate : AbstractSchemaModificationInterpreter() {
-    val Arguments.receiver: GroupBy by arg()
+    val Arguments.receiver: GroupBy by groupBy()
     val Arguments.body: FirAnonymousFunctionExpression by arg(lens = Interpreter.Id)
     override fun Arguments.interpret(): PluginDataFrameSchema {
         return aggregate(
@@ -87,7 +90,7 @@ fun KotlinTypeFacade.aggregate(
             )
         }
 
-        val cols = createPluginDataFrameSchema(groupBy.keys, groupBy.moveToTop).columns() + dsl.columns.map {
+        val cols = groupBy.keys.columns() + dsl.columns.map {
             simpleColumnOf(it.name, it.type)
         }
         PluginDataFrameSchema(cols)
@@ -144,13 +147,23 @@ fun KotlinTypeFacade.createPluginDataFrameSchema(keys: List<ColumnWithPathApprox
 }
 
 class GroupByToDataFrame : AbstractSchemaModificationInterpreter() {
-    val Arguments.receiver: GroupBy by arg()
+    val Arguments.receiver: GroupBy by groupBy()
     val Arguments.groupedColumnName: String? by arg(defaultValue = Present(null))
 
     override fun Arguments.interpret(): PluginDataFrameSchema {
-        val grouped = listOf(SimpleFrameColumn(groupedColumnName ?: "group", receiver.df.columns()))
+        val grouped = listOf(SimpleFrameColumn(groupedColumnName ?: "group", receiver.groups.columns()))
         return PluginDataFrameSchema(
-            createPluginDataFrameSchema(receiver.keys, receiver.moveToTop).columns() + grouped
+            receiver.keys.columns() + grouped
         )
     }
 }
+
+class GroupByAdd : AbstractInterpreter<GroupBy>() {
+    val Arguments.receiver: GroupBy by groupBy()
+    val Arguments.name: String by arg()
+    val Arguments.type: TypeApproximation by type(name("expression"))
+
+    override fun Arguments.interpret(): GroupBy {
+        return GroupBy(receiver.keys, receiver.groups.add(name, type.type, context = this))
+    }
+}
diff --git a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/interpret.kt b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/interpret.kt
index 2c8fe0098f..de690d00ba 100644
--- a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/interpret.kt
+++ b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/interpret.kt
@@ -36,6 +36,7 @@ import org.jetbrains.kotlin.fir.references.resolved
 import org.jetbrains.kotlin.fir.references.symbol
 import org.jetbrains.kotlin.fir.references.toResolvedCallableSymbol
 import org.jetbrains.kotlin.fir.resolve.fqName
+import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.scopes.collectAllProperties
 import org.jetbrains.kotlin.fir.scopes.getProperties
 import org.jetbrains.kotlin.fir.scopes.impl.declaredMemberScope
@@ -78,6 +79,7 @@ import org.jetbrains.kotlinx.dataframe.plugin.impl.SimpleDataColumn
 import org.jetbrains.kotlinx.dataframe.plugin.impl.SimpleColumnGroup
 import org.jetbrains.kotlinx.dataframe.plugin.impl.SimpleFrameColumn
 import org.jetbrains.kotlinx.dataframe.plugin.impl.api.ColumnsResolver
+import org.jetbrains.kotlinx.dataframe.plugin.impl.api.GroupBy
 import org.jetbrains.kotlinx.dataframe.plugin.impl.api.SingleColumnApproximation
 import org.jetbrains.kotlinx.dataframe.plugin.impl.api.TypeApproximation
 
@@ -277,6 +279,17 @@ fun <T> KotlinTypeFacade.interpret(
                 }
             }
 
+            is Interpreter.GroupBy -> {
+                assert(expectedReturnType.toString() == GroupBy::class.qualifiedName!!) {
+                    "'$name' should be ${GroupBy::class.qualifiedName!!}, but plugin expect $expectedReturnType"
+                }
+
+                val resolvedType = it.expression.resolvedType.fullyExpandedType(session)
+                val keys = pluginDataFrameSchema(resolvedType.typeArguments[0])
+                val groups = pluginDataFrameSchema(resolvedType.typeArguments[1])
+                Interpreter.Success(GroupBy(keys, groups))
+            }
+
             is Interpreter.Id -> {
                 Interpreter.Success(it.expression)
             }
diff --git a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/loadInterpreter.kt b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/loadInterpreter.kt
index 4d3db8733f..45dc022423 100644
--- a/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/loadInterpreter.kt
+++ b/plugins/kotlin-dataframe/src/org/jetbrains/kotlinx/dataframe/plugin/loadInterpreter.kt
@@ -88,6 +88,7 @@ import org.jetbrains.kotlinx.dataframe.plugin.impl.api.FillNulls0
 import org.jetbrains.kotlinx.dataframe.plugin.impl.api.Flatten0
 import org.jetbrains.kotlinx.dataframe.plugin.impl.api.FlattenDefault
 import org.jetbrains.kotlinx.dataframe.plugin.impl.api.FrameCols0
+import org.jetbrains.kotlinx.dataframe.plugin.impl.api.GroupByAdd
 import org.jetbrains.kotlinx.dataframe.plugin.impl.api.MapToFrame
 import org.jetbrains.kotlinx.dataframe.plugin.impl.api.Move0
 import org.jetbrains.kotlinx.dataframe.plugin.impl.api.MoveAfter0
@@ -275,6 +276,7 @@ internal inline fun <reified T> String.load(): T {
         "MoveToLeft1" -> MoveToLeft1()
         "MoveToRight0" -> MoveToRight0()
         "MoveAfter0" -> MoveAfter0()
+        "GroupByAdd" -> GroupByAdd()
         else -> error("$this")
     } as T
 }
diff --git a/plugins/kotlin-dataframe/testData/box/groupByAdd.kt b/plugins/kotlin-dataframe/testData/box/groupByAdd.kt
new file mode 100644
index 0000000000..68ccfda00f
--- /dev/null
+++ b/plugins/kotlin-dataframe/testData/box/groupByAdd.kt
@@ -0,0 +1,42 @@
+import org.jetbrains.kotlinx.dataframe.*
+import org.jetbrains.kotlinx.dataframe.annotations.*
+import org.jetbrains.kotlinx.dataframe.api.*
+import org.jetbrains.kotlinx.dataframe.api.groupBy
+import org.jetbrains.kotlinx.dataframe.io.*
+
+enum class State {
+    Idle,
+    Productive,
+    Maintenance,
+}
+
+class Event(val toolId: String, val state: State, val timestamp: Long)
+
+fun box(): String {
+    val tool1 = "tool_1"
+    val tool2 = "tool_2"
+    val tool3 = "tool_3"
+
+    val events = listOf(
+        Event(tool1, State.Idle, 0),
+        Event(tool1, State.Productive, 5),
+        Event(tool2, State.Idle, 0),
+        Event(tool2, State.Maintenance, 10),
+        Event(tool2, State.Idle, 20),
+        Event(tool3, State.Idle, 0),
+        Event(tool3, State.Productive, 25),
+    ).toDataFrame()
+
+    val lastTimestamp = events.maxOf { timestamp }
+    val groupBy = events
+        .groupBy { toolId }
+        .sortBy { timestamp }
+        .add("stateDuration") {
+            (next()?.timestamp ?: lastTimestamp) - timestamp
+        }.toDataFrame()
+
+    groupBy.group[0].stateDuration
+
+    groupBy.compareSchemas(strict = true)
+    return "OK"
+}
diff --git a/plugins/kotlin-dataframe/testData/box/groupBy_extractSchema.kt b/plugins/kotlin-dataframe/testData/box/groupBy_extractSchema.kt
new file mode 100644
index 0000000000..c7efc8a953
--- /dev/null
+++ b/plugins/kotlin-dataframe/testData/box/groupBy_extractSchema.kt
@@ -0,0 +1,14 @@
+import org.jetbrains.kotlinx.dataframe.*
+import org.jetbrains.kotlinx.dataframe.annotations.*
+import org.jetbrains.kotlinx.dataframe.api.*
+import org.jetbrains.kotlinx.dataframe.io.*
+
+fun box(): String {
+    val df = dataFrameOf("a", "b", "c")(1, 2, 3)
+
+    val groupBy = df.groupBy { a }
+
+    val df1 = groupBy.updateGroups { it.remove { a } }.toDataFrame()
+    df1.compileTimeSchema().print()
+    return "OK"
+}
diff --git a/plugins/kotlin-dataframe/tests-gen/org/jetbrains/kotlin/fir/dataframe/DataFrameBlackBoxCodegenTestGenerated.java b/plugins/kotlin-dataframe/tests-gen/org/jetbrains/kotlin/fir/dataframe/DataFrameBlackBoxCodegenTestGenerated.java
index 48887c251b..943be4285c 100644
--- a/plugins/kotlin-dataframe/tests-gen/org/jetbrains/kotlin/fir/dataframe/DataFrameBlackBoxCodegenTestGenerated.java
+++ b/plugins/kotlin-dataframe/tests-gen/org/jetbrains/kotlin/fir/dataframe/DataFrameBlackBoxCodegenTestGenerated.java
@@ -214,12 +214,24 @@ public void testGroupBy() {
     runTest("testData/box/groupBy.kt");
   }
 
+  @Test
+  @TestMetadata("groupByAdd.kt")
+  public void testGroupByAdd() {
+    runTest("testData/box/groupByAdd.kt");
+  }
+
   @Test
   @TestMetadata("groupBy_DataRow.kt")
   public void testGroupBy_DataRow() {
     runTest("testData/box/groupBy_DataRow.kt");
   }
 
+  @Test
+  @TestMetadata("groupBy_extractSchema.kt")
+  public void testGroupBy_extractSchema() {
+    runTest("testData/box/groupBy_extractSchema.kt");
+  }
+
   @Test
   @TestMetadata("groupBy_refine.kt")
   public void testGroupBy_refine() {