diff --git a/fleet/lsp.protocol/srcCommonMain/com/jetbrains/lsp/protocol/TypeHierarchy.kt b/fleet/lsp.protocol/srcCommonMain/com/jetbrains/lsp/protocol/TypeHierarchy.kt
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+// Copyright 2000-2025 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.jetbrains.lsp.protocol
+
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.builtins.ListSerializer
+import kotlinx.serialization.builtins.nullable
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.json.JsonElement
+
+/**
+ * The parameter of a `textDocument/prepareTypeHierarchy` request.
+ *
+ * @since 3.17.0
+ * @see <a href="https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#typeHierarchyPrepareParams">typeHierarchyPrepareParams (LSP spec)</a>
+ */
+@Serializable
+data class TypeHierarchyPrepareParams(
+  override val textDocument: TextDocumentIdentifier,
+  override val position: Position,
+  override val workDoneToken: ProgressToken? = null,
+) : TextDocumentPositionParams, WorkDoneProgressParams
+
+/**
+ * The parameter of a `typeHierarchy/supertypes` request.
+ *
+ * @since 3.17.0
+ * @see <a href="https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#typeHierarchySupertypesParams">typeHierarchySupertypesParams (LSP spec)</a>
+ */
+@Serializable
+data class TypeHierarchySupertypesParams(
+  val item: TypeHierarchyItem,
+  override val partialResultToken: ProgressToken? = null,
+  override val workDoneToken: ProgressToken? = null,
+) : WorkDoneProgressParams, PartialResultParams
+
+/**
+ * The parameter of a `typeHierarchy/subtypes` request.
+ *
+ * @since 3.17.0
+ * @see <a href="https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#typeHierarchySubtypesParams">typeHierarchySubtypesParams (LSP spec)</a>
+ */
+@Serializable
+data class TypeHierarchySubtypesParams(
+  val item: TypeHierarchyItem,
+  override val partialResultToken: ProgressToken? = null,
+  override val workDoneToken: ProgressToken? = null,
+) : WorkDoneProgressParams, PartialResultParams
+
+/**
+ * Represents an item in the type hierarchy.
+ *
+ * @since 3.17.0
+ * @see <a href="https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#typeHierarchyItem">typeHierarchyItem (LSP spec)</a>
+ */
+@Serializable
+data class TypeHierarchyItem(
+  /**
+   * The name of this item.
+   */
+  val name: String,
+
+  /**
+   * The kind of this item.
+   */
+  val kind: SymbolKind,
+
+  /**
+   * Tags for this item.
+   */
+  val tags: List<SymbolTag>? = null,
+
+  /**
+   * More detail for this item, e.g. the signature of a function.
+   */
+  val detail: String? = null,
+
+  /**
+   * The resource identifier of this item.
+   */
+  val uri: DocumentUri,
+
+  /**
+   * The range enclosing this symbol not including leading/trailing whitespace
+   * but everything else, e.g. comments and code.
+   */
+  val range: Range,
+
+  /**
+   * The range that should be selected and revealed when this symbol is being
+   * picked, e.g. the name of a function. Must be contained by the
+   * {@link TypeHierarchyItem.range `range`}.
+   */
+  val selectionRange: Range,
+
+  /**
+   * A data entry field that is preserved between a type hierarchy prepare and
+   * supertypes or subtypes requests. It could also be used to identify the
+   * type hierarchy in the server, helping improve the performance on
+   * resolving supertypes and subtypes.
+   */
+  val data: JsonElement? = null,
+)
+
+object TypeHierarchyRequests {
+  /**
+   * @see <a href="https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#textDocument_prepareTypeHierarchy">textDocument/prepareTypeHierarchy</a>
+   */
+  val PrepareTypeHierarchyRequestType: RequestType<TypeHierarchyPrepareParams, List<TypeHierarchyItem>?, Unit> = RequestType(
+    method = "textDocument/prepareTypeHierarchy",
+    paramsSerializer = TypeHierarchyPrepareParams.serializer(),
+    resultSerializer = ListSerializer(elementSerializer = TypeHierarchyItem.serializer()).nullable,
+    errorSerializer = Unit.serializer(),
+  )
+
+  /**
+   * @see <a href="https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#typeHierarchy_supertypes">typeHierarchy/supertypes</a>
+   */
+  val SupertypesRequestType: RequestType<TypeHierarchySupertypesParams, List<TypeHierarchyItem>?, Unit> = RequestType(
+    method = "typeHierarchy/supertypes",
+    paramsSerializer = TypeHierarchySupertypesParams.serializer(),
+    resultSerializer = ListSerializer(elementSerializer = TypeHierarchyItem.serializer()).nullable,
+    errorSerializer = Unit.serializer(),
+  )
+
+  /**
+   * @see <a href="https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#typeHierarchy_subtypes">typeHierarchy/subtypes</a>
+   */
+  val SubtypesRequestType: RequestType<TypeHierarchySubtypesParams, List<TypeHierarchyItem>?, Unit> = RequestType(
+    method = "typeHierarchy/subtypes",
+    paramsSerializer = TypeHierarchySubtypesParams.serializer(),
+    resultSerializer = ListSerializer(elementSerializer = TypeHierarchyItem.serializer()).nullable,
+    errorSerializer = Unit.serializer(),
+  )
+}