diff --git a/Sources/BuildServerIntegration/BuildServerManager.swift b/Sources/BuildServerIntegration/BuildServerManager.swift
index a19ed0576..0f648180e 100644
--- a/Sources/BuildServerIntegration/BuildServerManager.swift
+++ b/Sources/BuildServerIntegration/BuildServerManager.swift
@@ -795,6 +795,28 @@ package actor BuildServerManager: QueueBasedMessageHandler {
     return languageFromBuildServer ?? Language(inferredFromFileExtension: document)
   }
 
+  /// Returns the language that a document should be interpreted in for background tasks where the editor doesn't
+  /// specify the document's language.
+  ///
+  /// If the language could not be determined, this method throws an error.
+  package func defaultLanguageInCanonicalTarget(for document: DocumentURI) async throws -> Language {
+    struct UnableToInferLanguage: Error, CustomStringConvertible {
+      let document: DocumentURI
+      var description: String { "Unable to infer language for \(document)" }
+    }
+
+    guard let canonicalTarget = await self.canonicalTarget(for: document) else {
+      guard let language = Language(inferredFromFileExtension: document) else {
+        throw UnableToInferLanguage(document: document)
+      }
+      return language
+    }
+    guard let language = await defaultLanguage(for: document, in: canonicalTarget) else {
+      throw UnableToInferLanguage(document: document)
+    }
+    return language
+  }
+
   /// Retrieve information about the given source file within the build server.
   package func sourceFileInfo(for document: DocumentURI) async -> SourceFileInfo? {
     return await orLog("Getting targets for source file") {
diff --git a/Sources/ClangLanguageService/ClangLanguageService.swift b/Sources/ClangLanguageService/ClangLanguageService.swift
index 7bacff369..a5487a6db 100644
--- a/Sources/ClangLanguageService/ClangLanguageService.swift
+++ b/Sources/ClangLanguageService/ClangLanguageService.swift
@@ -496,14 +496,10 @@ extension ClangLanguageService {
   }
 
   package func doccDocumentation(_ req: DoccDocumentationRequest) async throws -> DoccDocumentationResponse {
-    guard let sourceKitLSPServer else {
-      throw ResponseError.unknown("Connection to the editor closed")
+    guard let language = openDocuments[req.textDocument.uri] else {
+      throw ResponseError.requestFailed("Documentation preview is not available for clang files")
     }
-
-    let snapshot = try sourceKitLSPServer.documentManager.latestSnapshot(req.textDocument.uri)
-    throw ResponseError.requestFailed(
-      "Documentation preview is not available for \(snapshot.language.description) files"
-    )
+    throw ResponseError.requestFailed("Documentation preview is not available for \(language.description) files")
   }
 
   package func symbolInfo(_ req: SymbolInfoRequest) async throws -> [SymbolDetails] {
diff --git a/Sources/DocumentationLanguageService/DoccDocumentationError.swift b/Sources/DocumentationLanguageService/DoccDocumentationError.swift
index ad1956884..07247a348 100644
--- a/Sources/DocumentationLanguageService/DoccDocumentationError.swift
+++ b/Sources/DocumentationLanguageService/DoccDocumentationError.swift
@@ -23,7 +23,7 @@ enum DocCDocumentationError: LocalizedError {
     case .unsupportedLanguage(let language):
       return "Documentation preview is not available for \(language.description) files"
     case .indexNotAvailable:
-      return "The index is not availble to complete the request"
+      return "The index is not available to complete the request"
     case .symbolNotFound(let symbolName):
       return "Could not find symbol \(symbolName) in the project"
     }
diff --git a/Sources/DocumentationLanguageService/DoccDocumentationHandler.swift b/Sources/DocumentationLanguageService/DoccDocumentationHandler.swift
index 5466019e9..2d3912ebd 100644
--- a/Sources/DocumentationLanguageService/DoccDocumentationHandler.swift
+++ b/Sources/DocumentationLanguageService/DoccDocumentationHandler.swift
@@ -104,47 +104,35 @@ extension DocumentationLanguageService {
       guard let index = workspace.index(checkedFor: .deletedFiles) else {
         throw ResponseError.requestFailed(doccDocumentationError: .indexNotAvailable)
       }
-      guard let symbolLink = DocCSymbolLink(linkString: symbolName),
-        let symbolOccurrence = try await index.primaryDefinitionOrDeclarationOccurrence(
-          ofDocCSymbolLink: symbolLink,
-          fetchSymbolGraph: { location in
-            guard let symbolWorkspace = await sourceKitLSPServer.workspaceForDocument(uri: location.documentUri) else {
-              throw ResponseError.internalError("Unable to find language service for \(location.documentUri)")
+      return try await sourceKitLSPServer.withOnDiskDocumentManager { onDiskDocumentManager in
+        guard let symbolLink = DocCSymbolLink(linkString: symbolName),
+          let symbolOccurrence = try await index.primaryDefinitionOrDeclarationOccurrence(
+            ofDocCSymbolLink: symbolLink,
+            fetchSymbolGraph: { location in
+              return try await sourceKitLSPServer.primaryLanguageService(
+                for: location.documentUri,
+                workspace.buildServerManager.defaultLanguageInCanonicalTarget(for: location.documentUri),
+                in: workspace
+              )
+              .symbolGraph(forOnDiskContentsAt: location, in: workspace, manager: onDiskDocumentManager)
             }
-            let languageService = try await sourceKitLSPServer.primaryLanguageService(
-              for: location.documentUri,
-              .swift,
-              in: symbolWorkspace
-            )
-            return try await languageService.symbolGraph(
-              forOnDiskContentsOf: location.documentUri,
-              at: location
-            )
-          }
+          )
+        else {
+          throw ResponseError.requestFailed(doccDocumentationError: .symbolNotFound(symbolName))
+        }
+        let symbolGraph = try await sourceKitLSPServer.primaryLanguageService(
+          for: symbolOccurrence.location.documentUri,
+          workspace.buildServerManager.defaultLanguageInCanonicalTarget(for: symbolOccurrence.location.documentUri),
+          in: workspace
+        ).symbolGraph(forOnDiskContentsAt: symbolOccurrence.location, in: workspace, manager: onDiskDocumentManager)
+        return try await documentationManager.renderDocCDocumentation(
+          symbolUSR: symbolOccurrence.symbol.usr,
+          symbolGraph: symbolGraph,
+          markupFile: snapshot.text,
+          moduleName: moduleName,
+          catalogURL: catalogURL
         )
-      else {
-        throw ResponseError.requestFailed(doccDocumentationError: .symbolNotFound(symbolName))
       }
-      let symbolDocumentUri = symbolOccurrence.location.documentUri
-      guard let symbolWorkspace = await sourceKitLSPServer.workspaceForDocument(uri: symbolDocumentUri) else {
-        throw ResponseError.internalError("Unable to find language service for \(symbolDocumentUri)")
-      }
-      let languageService = try await sourceKitLSPServer.primaryLanguageService(
-        for: symbolDocumentUri,
-        .swift,
-        in: symbolWorkspace
-      )
-      let symbolGraph = try await languageService.symbolGraph(
-        forOnDiskContentsOf: symbolDocumentUri,
-        at: symbolOccurrence.location
-      )
-      return try await documentationManager.renderDocCDocumentation(
-        symbolUSR: symbolOccurrence.symbol.usr,
-        symbolGraph: symbolGraph,
-        markupFile: snapshot.text,
-        moduleName: moduleName,
-        catalogURL: catalogURL
-      )
     }
     // This is a page representing the module itself.
     // Create a dummy symbol graph and tell SwiftDocC to convert the module name.
@@ -175,24 +163,26 @@ extension DocumentationLanguageService {
       in: workspace
     ).symbolGraph(for: snapshot, at: position)
     // Locate the documentation extension and include it in the request if one exists
-    let markupExtensionFile = await orLog("Finding markup extension file for symbol \(symbolUSR)") {
-      try await findMarkupExtensionFile(
-        workspace: workspace,
-        documentationManager: documentationManager,
-        catalogURL: catalogURL,
-        for: symbolUSR,
-        fetchSymbolGraph: { location in
-          guard let symbolWorkspace = await sourceKitLSPServer.workspaceForDocument(uri: location.documentUri) else {
-            throw ResponseError.internalError("Unable to find language service for \(location.documentUri)")
+    let markupExtensionFile = await sourceKitLSPServer.withOnDiskDocumentManager {
+      [documentationManager, documentManager = try documentManager] onDiskDocumentManager in
+      await orLog("Finding markup extension file for symbol \(symbolUSR)") {
+        try await Self.findMarkupExtensionFile(
+          workspace: workspace,
+          documentationManager: documentationManager,
+          documentManager: documentManager,
+          catalogURL: catalogURL,
+          for: symbolUSR,
+          fetchSymbolGraph: { location in
+            try await sourceKitLSPServer.primaryLanguageService(
+              for: location.documentUri,
+              snapshot.language,
+              in: workspace
+            )
+            .symbolGraph(forOnDiskContentsAt: location, in: workspace, manager: onDiskDocumentManager)
+
           }
-          let languageService = try await sourceKitLSPServer.primaryLanguageService(
-            for: location.documentUri,
-            .swift,
-            in: symbolWorkspace
-          )
-          return try await languageService.symbolGraph(forOnDiskContentsOf: location.documentUri, at: location)
-        }
-      )
+        )
+      }
     }
     return try await documentationManager.renderDocCDocumentation(
       symbolUSR: symbolUSR,
@@ -204,9 +194,10 @@ extension DocumentationLanguageService {
     )
   }
 
-  private func findMarkupExtensionFile(
+  private static func findMarkupExtensionFile(
     workspace: Workspace,
     documentationManager: DocCDocumentationManager,
+    documentManager: DocumentManager,
     catalogURL: URL?,
     for symbolUSR: String,
     fetchSymbolGraph: @Sendable (SymbolLocation) async throws -> String?
@@ -215,16 +206,17 @@ extension DocumentationLanguageService {
       return nil
     }
     let catalogIndex = try await documentationManager.catalogIndex(for: catalogURL)
-    guard let index = workspace.index(checkedFor: .deletedFiles),
-      let symbolInformation = try await index.doccSymbolInformation(
-        ofUSR: symbolUSR,
-        fetchSymbolGraph: fetchSymbolGraph
-      ),
-      let markupExtensionFileURL = catalogIndex.documentationExtension(for: symbolInformation)
-    else {
+    guard let index = workspace.index(checkedFor: .deletedFiles) else {
+      return nil
+    }
+    let symbolInformation = try await index.doccSymbolInformation(
+      ofUSR: symbolUSR,
+      fetchSymbolGraph: fetchSymbolGraph
+    )
+    guard let markupExtensionFileURL = catalogIndex.documentationExtension(for: symbolInformation) else {
       return nil
     }
-    return try? documentManager.latestSnapshotOrDisk(
+    return documentManager.latestSnapshotOrDisk(
       DocumentURI(markupExtensionFileURL),
       language: .markdown
     )?.text
diff --git a/Sources/DocumentationLanguageService/IndexStoreDB+Extensions.swift b/Sources/DocumentationLanguageService/IndexStoreDB+Extensions.swift
index bc817448a..fe5922ddd 100644
--- a/Sources/DocumentationLanguageService/IndexStoreDB+Extensions.swift
+++ b/Sources/DocumentationLanguageService/IndexStoreDB+Extensions.swift
@@ -40,7 +40,7 @@ extension CheckedIndex {
     var result: [SymbolOccurrence] = []
     for occurrence in topLevelSymbolOccurrences {
       let info = try await doccSymbolInformation(ofUSR: occurrence.symbol.usr, fetchSymbolGraph: fetchSymbolGraph)
-      if let info, info.matches(symbolLink) {
+      if info.matches(symbolLink) {
         result.append(occurrence)
       }
     }
@@ -60,9 +60,9 @@ extension CheckedIndex {
   func doccSymbolInformation(
     ofUSR usr: String,
     fetchSymbolGraph: (SymbolLocation) async throws -> String?
-  ) async throws -> DocCSymbolInformation? {
+  ) async throws -> DocCSymbolInformation {
     guard let topLevelSymbolOccurrence = primaryDefinitionOrDeclarationOccurrence(ofUSR: usr) else {
-      return nil
+      throw DocCCheckedIndexError.emptyDocCSymbolLink
     }
     let moduleName = topLevelSymbolOccurrence.location.moduleName
     var symbols = [topLevelSymbolOccurrence]
diff --git a/Sources/SourceKitLSP/CMakeLists.txt b/Sources/SourceKitLSP/CMakeLists.txt
index 1536bd6c5..7b9677fff 100644
--- a/Sources/SourceKitLSP/CMakeLists.txt
+++ b/Sources/SourceKitLSP/CMakeLists.txt
@@ -13,6 +13,7 @@ add_library(SourceKitLSP STATIC
   LogMessageNotification+representingStructureUsingEmojiPrefixIfNecessary.swift
   MacroExpansionReferenceDocumentURLData.swift
   MessageHandlingDependencyTracker.swift
+  OnDiskDocumentManager.swift
   ReferenceDocumentURL.swift
   Rename.swift
   SemanticTokensLegend+SourceKitLSPLegend.swift
diff --git a/Sources/SourceKitLSP/LanguageService.swift b/Sources/SourceKitLSP/LanguageService.swift
index ddadbebd2..a8c27e43a 100644
--- a/Sources/SourceKitLSP/LanguageService.swift
+++ b/Sources/SourceKitLSP/LanguageService.swift
@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+package import BuildServerIntegration
 import Foundation
 package import IndexStoreDB
 package import LanguageServerProtocol
@@ -148,6 +149,18 @@ package protocol LanguageService: AnyObject, Sendable {
   /// Sent to close a document on the Language Server.
   func closeDocument(_ notification: DidCloseTextDocumentNotification) async
 
+  /// Sent to open up a document on the Language Server whose contents are on-disk.
+  ///
+  /// The snapshot will have a synthesized name and the caller is responsible for synthesizing build settings for it.
+  ///
+  /// - Important: This should only be called by `OnDiskDocumentManager`.
+  func openOnDiskDocument(snapshot: DocumentSnapshot, buildSettings: FileBuildSettings) async throws
+
+  /// Sent to close a document that was opened by `openOnDiskDocument`.
+  ///
+  /// - Important: This should only be called by `OnDiskDocumentManager`.
+  func closeOnDiskDocument(uri: DocumentURI) async throws
+
   /// Re-open the given document, discarding any in-memory state and forcing an AST to be re-built after build settings
   /// have been changed. This needs to be handled via a notification to ensure that no other request for this document
   /// is executing at the same time.
@@ -197,8 +210,9 @@ package protocol LanguageService: AnyObject, Sendable {
   /// Return the symbol graph at the given location for the contents of the document as they are on-disk (opposed to the
   /// in-memory modified version of the document).
   func symbolGraph(
-    forOnDiskContentsOf symbolDocumentUri: DocumentURI,
-    at location: SymbolLocation
+    forOnDiskContentsAt location: SymbolLocation,
+    in workspace: Workspace,
+    manager: OnDiskDocumentManager
   ) async throws -> String
 
   /// Request a generated interface of a module to display in the IDE.
@@ -330,6 +344,14 @@ package extension LanguageService {
 
   func clientInitialized(_ initialized: LanguageServerProtocol.InitializedNotification) async {}
 
+  func openOnDiskDocument(snapshot: DocumentSnapshot, buildSettings: FileBuildSettings) async throws {
+    throw ResponseError.unknown("\(#function) not implemented in \(Self.self)")
+  }
+
+  func closeOnDiskDocument(uri: DocumentURI) async throws {
+    throw ResponseError.unknown("\(#function) not implemented in \(Self.self)")
+  }
+
   func willSaveDocument(_ notification: WillSaveTextDocumentNotification) async {}
 
   func didSaveDocument(_ notification: DidSaveTextDocumentNotification) async {}
@@ -368,8 +390,9 @@ package extension LanguageService {
   }
 
   func symbolGraph(
-    forOnDiskContentsOf symbolDocumentUri: DocumentURI,
-    at location: SymbolLocation
+    forOnDiskContentsAt location: SymbolLocation,
+    in workspace: Workspace,
+    manager: OnDiskDocumentManager
   ) async throws -> String {
     throw ResponseError.internalError("\(#function) not implemented in \(Self.self)")
   }
diff --git a/Sources/SourceKitLSP/OnDiskDocumentManager.swift b/Sources/SourceKitLSP/OnDiskDocumentManager.swift
new file mode 100644
index 000000000..f66610e05
--- /dev/null
+++ b/Sources/SourceKitLSP/OnDiskDocumentManager.swift
@@ -0,0 +1,95 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+package import BuildServerIntegration
+import Foundation
+package import LanguageServerProtocol
+import SKLogging
+import SKUtilities
+import SwiftExtensions
+
+package actor OnDiskDocumentManager {
+  private let sourceKitLSPServer: SourceKitLSPServer
+  private var openSnapshots:
+    [DocumentURI: (snapshot: DocumentSnapshot, buildSettings: FileBuildSettings, workspace: Workspace)]
+
+  fileprivate init(sourceKitLSPServer: SourceKitLSPServer) {
+    self.sourceKitLSPServer = sourceKitLSPServer
+    openSnapshots = [:]
+  }
+
+  /// Opens a dummy ``DocumentSnapshot`` with contents from disk for a given ``DocumentURI`` and ``Language``.
+  ///
+  /// The snapshot will remain cached until ``closeAllDocuments()`` is called.
+  package func open(
+    uri: DocumentURI,
+    language: Language,
+    in workspace: Workspace
+  ) async throws -> (snapshot: DocumentSnapshot, buildSettings: FileBuildSettings) {
+    guard let fileURL = uri.fileURL else {
+      throw ResponseError.unknown("Cannot create snapshot with on-disk contents for non-file URI \(uri.forLogging)")
+    }
+
+    if let cachedSnapshot = openSnapshots[uri] {
+      return (cachedSnapshot.snapshot, cachedSnapshot.buildSettings)
+    }
+
+    let snapshot = DocumentSnapshot(
+      uri: try DocumentURI(filePath: "\(UUID().uuidString)/\(fileURL.filePath)", isDirectory: false),
+      language: language,
+      version: 0,
+      lineTable: LineTable(try String(contentsOf: fileURL, encoding: .utf8))
+    )
+    let languageService = try await sourceKitLSPServer.primaryLanguageService(for: uri, language, in: workspace)
+
+    let originalBuildSettings = await workspace.buildServerManager.buildSettingsInferredFromMainFile(
+      for: uri,
+      language: language,
+      fallbackAfterTimeout: false
+    )
+    guard let originalBuildSettings else {
+      throw ResponseError.unknown("Failed to infer build settings for \(uri)")
+    }
+    let patchedBuildSettings = originalBuildSettings.patching(newFile: snapshot.uri, originalFile: uri)
+    try await languageService.openOnDiskDocument(snapshot: snapshot, buildSettings: patchedBuildSettings)
+    openSnapshots[uri] = (snapshot, patchedBuildSettings, workspace)
+    return (snapshot, patchedBuildSettings)
+  }
+
+  /// Close all of the ``DocumentSnapshot``s that were opened by this ``OnDiskDocumentManager``.
+  fileprivate func closeAllDocuments() async {
+    for (snapshot, _, workspace) in openSnapshots.values {
+      await orLog("Closing snapshot from on-disk contents: \(snapshot.uri.forLogging)") {
+        let languageService =
+          try await sourceKitLSPServer.primaryLanguageService(for: snapshot.uri, snapshot.language, in: workspace)
+        try await languageService.closeOnDiskDocument(uri: snapshot.uri)
+      }
+    }
+    openSnapshots = [:]
+  }
+}
+
+package extension SourceKitLSPServer {
+  nonisolated func withOnDiskDocumentManager<T>(
+    _ body: (OnDiskDocumentManager) async throws -> T
+  ) async rethrows -> T {
+    let manager = OnDiskDocumentManager(sourceKitLSPServer: self)
+    do {
+      let result = try await body(manager)
+      await manager.closeAllDocuments()
+      return result
+    } catch {
+      await manager.closeAllDocuments()
+      throw error
+    }
+  }
+}
diff --git a/Sources/SwiftLanguageService/CMakeLists.txt b/Sources/SwiftLanguageService/CMakeLists.txt
index c08eaad6d..acf5d37f6 100644
--- a/Sources/SwiftLanguageService/CMakeLists.txt
+++ b/Sources/SwiftLanguageService/CMakeLists.txt
@@ -21,7 +21,6 @@ add_library(SwiftLanguageService STATIC
   SemanticRefactorCommand.swift
   DocumentFormatting.swift
   DiagnosticReportManager.swift
-  WithSnapshotFromDiskOpenedInSourcekitd.swift
   SemanticTokens.swift
   ExpandMacroCommand.swift
   Diagnostic.swift
diff --git a/Sources/SwiftLanguageService/SwiftLanguageService.swift b/Sources/SwiftLanguageService/SwiftLanguageService.swift
index 6ce44fdf8..759102a4e 100644
--- a/Sources/SwiftLanguageService/SwiftLanguageService.swift
+++ b/Sources/SwiftLanguageService/SwiftLanguageService.swift
@@ -294,29 +294,24 @@ package actor SwiftLanguageService: LanguageService, Sendable {
     }
   }
 
-  func buildSettings(for document: DocumentURI, fallbackAfterTimeout: Bool) async -> FileBuildSettings? {
-    let buildSettingsFile = document.buildSettingsFile
-
+  func compileCommand(for document: DocumentURI, fallbackAfterTimeout: Bool) async -> SwiftCompileCommand? {
     guard let sourceKitLSPServer else {
       logger.fault("Cannot retrieve build settings because SourceKitLSPServer is no longer alive")
       return nil
     }
-    guard let workspace = await sourceKitLSPServer.workspaceForDocument(uri: buildSettingsFile) else {
+    guard let workspace = await sourceKitLSPServer.workspaceForDocument(uri: document.buildSettingsFile) else {
       return nil
     }
-    return await workspace.buildServerManager.buildSettingsInferredFromMainFile(
-      for: buildSettingsFile,
+    let settings = await workspace.buildServerManager.buildSettingsInferredFromMainFile(
+      for: document.buildSettingsFile,
       language: .swift,
       fallbackAfterTimeout: fallbackAfterTimeout
     )
-  }
 
-  func compileCommand(for document: DocumentURI, fallbackAfterTimeout: Bool) async -> SwiftCompileCommand? {
-    if let settings = await self.buildSettings(for: document, fallbackAfterTimeout: fallbackAfterTimeout) {
-      return SwiftCompileCommand(settings)
-    } else {
+    guard let settings else {
       return nil
     }
+    return SwiftCompileCommand(settings)
   }
 
   func send(
@@ -586,6 +581,22 @@ extension SwiftLanguageService {
     }
   }
 
+  package func openOnDiskDocument(snapshot: DocumentSnapshot, buildSettings: FileBuildSettings) async throws {
+    _ = try await send(
+      sourcekitdRequest: \.editorOpen,
+      self.openDocumentSourcekitdRequest(snapshot: snapshot, compileCommand: SwiftCompileCommand(buildSettings)),
+      snapshot: snapshot
+    )
+  }
+
+  package func closeOnDiskDocument(uri: DocumentURI) async throws {
+    _ = try await send(
+      sourcekitdRequest: \.editorClose,
+      self.closeDocumentSourcekitdRequest(uri: uri),
+      snapshot: nil
+    )
+  }
+
   /// Cancels any in-flight tasks to send a `PublishedDiagnosticsNotification` after edits.
   private func cancelInFlightPublishDiagnosticsTask(for document: DocumentURI) {
     if let inFlightTask = inFlightPublishDiagnosticsTasks[document] {
diff --git a/Sources/SwiftLanguageService/SymbolGraph.swift b/Sources/SwiftLanguageService/SymbolGraph.swift
index ad922f349..7becaed9a 100644
--- a/Sources/SwiftLanguageService/SymbolGraph.swift
+++ b/Sources/SwiftLanguageService/SymbolGraph.swift
@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Copyright (c) 2025 Apple Inc. and the Swift project authors
 // Licensed under Apache License v2.0 with Runtime Library Exception
 //
 // See https://swift.org/LICENSE.txt for license information
@@ -10,6 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import BuildServerIntegration
 import Foundation
 package import IndexStoreDB
 package import LanguageServerProtocol
@@ -19,24 +20,22 @@ import SwiftSyntax
 
 extension SwiftLanguageService {
   package func symbolGraph(
-    forOnDiskContentsOf symbolDocumentUri: DocumentURI,
-    at location: SymbolLocation
+    forOnDiskContentsAt location: SymbolLocation,
+    in workspace: Workspace,
+    manager: OnDiskDocumentManager
   ) async throws -> String {
-    return try await withSnapshotFromDiskOpenedInSourcekitd(
-      uri: symbolDocumentUri,
-      fallbackSettingsAfterTimeout: false
-    ) { snapshot, compileCommand in
-      let symbolGraph = try await cursorInfo(
-        snapshot,
-        compileCommand: compileCommand,
-        Range(snapshot.position(of: location)),
-        includeSymbolGraph: true
-      ).symbolGraph
-      guard let symbolGraph else {
-        throw ResponseError.internalError("Unable to retrieve symbol graph")
-      }
-      return symbolGraph
+    let (snapshot, buildSettings) = try await manager.open(uri: location.documentUri, language: .swift, in: workspace)
+
+    let symbolGraph = try await cursorInfo(
+      snapshot,
+      compileCommand: SwiftCompileCommand(buildSettings),
+      Range(snapshot.position(of: location)),
+      includeSymbolGraph: true
+    ).symbolGraph
+    guard let symbolGraph else {
+      throw ResponseError.internalError("Unable to retrieve symbol graph")
     }
+    return symbolGraph
   }
 
   package func symbolGraph(
diff --git a/Sources/SwiftLanguageService/WithSnapshotFromDiskOpenedInSourcekitd.swift b/Sources/SwiftLanguageService/WithSnapshotFromDiskOpenedInSourcekitd.swift
deleted file mode 100644
index 2a38725c5..000000000
--- a/Sources/SwiftLanguageService/WithSnapshotFromDiskOpenedInSourcekitd.swift
+++ /dev/null
@@ -1,70 +0,0 @@
-//===----------------------------------------------------------------------===//
-//
-// This source file is part of the Swift.org open source project
-//
-// Copyright (c) 2014 - 2018 Apple Inc. and the Swift project authors
-// Licensed under Apache License v2.0 with Runtime Library Exception
-//
-// See https://swift.org/LICENSE.txt for license information
-// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
-//
-//===----------------------------------------------------------------------===//
-
-import BuildServerIntegration
-import Foundation
-import LanguageServerProtocol
-import SKLogging
-import SKUtilities
-import SourceKitLSP
-import SwiftExtensions
-
-extension SwiftLanguageService {
-  /// Open a unique dummy document in sourcekitd that has the contents of the file on disk for `uri` but an arbitrary
-  /// URI which doesn't exist on disk. Invoke `body` with a snapshot that contains the on-disk document contents and has
-  /// that dummy URI as well as build settings that were inferred from `uri` but have that URI replaced with the dummy
-  /// URI. Close the document in sourcekit after `body` has finished.
-  func withSnapshotFromDiskOpenedInSourcekitd<Result: Sendable>(
-    uri: DocumentURI,
-    fallbackSettingsAfterTimeout: Bool,
-    body: (_ snapshot: DocumentSnapshot, _ patchedCompileCommand: SwiftCompileCommand?) async throws -> Result
-  ) async throws -> Result {
-    guard let fileURL = uri.fileURL else {
-      throw ResponseError.unknown("Cannot create snapshot with on-disk contents for non-file URI \(uri.forLogging)")
-    }
-    let snapshot = DocumentSnapshot(
-      uri: try DocumentURI(filePath: "\(UUID().uuidString)/\(fileURL.filePath)", isDirectory: false),
-      language: .swift,
-      version: 0,
-      lineTable: LineTable(try String(contentsOf: fileURL, encoding: .utf8))
-    )
-    let patchedCompileCommand: SwiftCompileCommand? =
-      if let buildSettings = await self.buildSettings(
-        for: uri,
-        fallbackAfterTimeout: fallbackSettingsAfterTimeout
-      ) {
-        SwiftCompileCommand(buildSettings.patching(newFile: snapshot.uri, originalFile: uri))
-      } else {
-        nil
-      }
-
-    _ = try await send(
-      sourcekitdRequest: \.editorOpen,
-      self.openDocumentSourcekitdRequest(snapshot: snapshot, compileCommand: patchedCompileCommand),
-      snapshot: snapshot
-    )
-    let result: Swift.Result<Result, Error>
-    do {
-      result = .success(try await body(snapshot, patchedCompileCommand))
-    } catch {
-      result = .failure(error)
-    }
-    await orLog("Close helper document '\(snapshot.uri)' for cursorInfoFromDisk") {
-      _ = try await send(
-        sourcekitdRequest: \.editorClose,
-        self.closeDocumentSourcekitdRequest(uri: snapshot.uri),
-        snapshot: snapshot
-      )
-    }
-    return try result.get()
-  }
-}