diff --git a/Sources/BuildServerIntegration/BuildServerManagerDelegate.swift b/Sources/BuildServerIntegration/BuildServerManagerDelegate.swift
index 9fabb4b7..69145c3e 100644
--- a/Sources/BuildServerIntegration/BuildServerManagerDelegate.swift
+++ b/Sources/BuildServerIntegration/BuildServerManagerDelegate.swift
@@ -30,16 +30,6 @@ package protocol BuildServerManagerDelegate: AnyObject, Sendable {
   /// Notify the delegate that some information about the given build targets has changed and that it should recompute
   /// any information based on top of it.
   func buildTargetsChanged(_ changedTargets: Set<BuildTargetIdentifier>?) async
-
-  func addBuiltTargetListener(_ listener: any BuildTargetListener)
-
-  func removeBuiltTargetListener(_ listener: any BuildTargetListener)
-}
-
-package protocol BuildTargetListener: AnyObject, Sendable {
-  /// Notify the listener that some information about the given build targets has changed and that it should recompute
-  /// any information based on top of it.
-  func buildTargetsChanged(_ changedTargets: Set<BuildTargetIdentifier>?) async
 }
 
 /// Methods with which the `BuildServerManager` can send messages to the client (aka. editor).
diff --git a/Sources/ClangLanguageService/ClangLanguageService.swift b/Sources/ClangLanguageService/ClangLanguageService.swift
index 5595cc11..dd819993 100644
--- a/Sources/ClangLanguageService/ClangLanguageService.swift
+++ b/Sources/ClangLanguageService/ClangLanguageService.swift
@@ -644,11 +644,14 @@ extension ClangLanguageService {
     return nil
   }
 
-  package func syntacticTests(in workspace: Workspace) async -> [AnnotatedTestItem] {
+  package func syntacticTestItems(for snapshot: DocumentSnapshot) async -> [AnnotatedTestItem] {
     return []
   }
 
-  package func syntacticPlaygrounds(in workspace: Workspace) async -> [Playground] {
+  package func syntacticPlaygrounds(
+    for snapshot: DocumentSnapshot,
+    in workspace: Workspace
+  ) async -> [TextDocumentPlayground] {
     return []
   }
 
diff --git a/Sources/DocumentationLanguageService/DocumentationLanguageService.swift b/Sources/DocumentationLanguageService/DocumentationLanguageService.swift
index 282d0b4a..4386e6bd 100644
--- a/Sources/DocumentationLanguageService/DocumentationLanguageService.swift
+++ b/Sources/DocumentationLanguageService/DocumentationLanguageService.swift
@@ -88,11 +88,14 @@ package actor DocumentationLanguageService: LanguageService, Sendable {
     // The DocumentationLanguageService does not do anything with document events
   }
 
-  package func syntacticTests(in workspace: Workspace) async -> [AnnotatedTestItem] {
+  package func syntacticTestItems(for snapshot: DocumentSnapshot) async -> [AnnotatedTestItem] {
     return []
   }
 
-  package func syntacticPlaygrounds(in workspace: Workspace) async -> [Playground] {
+  package func syntacticPlaygrounds(
+    for snapshot: DocumentSnapshot,
+    in workspace: Workspace
+  ) async -> [TextDocumentPlayground] {
     return []
   }
 
diff --git a/Sources/SourceKitLSP/LanguageService.swift b/Sources/SourceKitLSP/LanguageService.swift
index 5ec6a59f..2294fdec 100644
--- a/Sources/SourceKitLSP/LanguageService.swift
+++ b/Sources/SourceKitLSP/LanguageService.swift
@@ -313,15 +313,20 @@ package protocol LanguageService: AnyObject, Sendable {
   /// A return value of `nil` indicates that this language service does not support syntactic test discovery.
   func syntacticDocumentTests(for uri: DocumentURI, in workspace: Workspace) async throws -> [AnnotatedTestItem]?
 
-  /// Returns the syntactically scanned tests declared within the workspace.
+  /// Syntactically scans the file at the given URL for tests declared within it.
+  ///
+  /// Does not write the results to the index.
   ///
   /// The order of the returned tests is not defined. The results should be sorted before being returned to the editor.
-  func syntacticTests(in workspace: Workspace) async -> [AnnotatedTestItem]
+  func syntacticTestItems(for snapshot: DocumentSnapshot) async -> [AnnotatedTestItem]
 
   /// Returns the syntactically scanned playgrounds declared within the workspace.
   ///
   /// The order of the returned playgrounds is not defined. The results should be sorted before being returned to the editor.
-  func syntacticPlaygrounds(in workspace: Workspace) async -> [Playground]
+  func syntacticPlaygrounds(
+    for snapshot: DocumentSnapshot,
+    in workspace: Workspace
+  ) async -> [TextDocumentPlayground]
 
   /// A position that is canonical for all positions within a declaration. For example, if we have the following
   /// declaration, then all `|` markers should return the same canonical position.
diff --git a/Sources/SourceKitLSP/PlaygroundDiscovery.swift b/Sources/SourceKitLSP/PlaygroundDiscovery.swift
index 2f9621b5..a5005242 100644
--- a/Sources/SourceKitLSP/PlaygroundDiscovery.swift
+++ b/Sources/SourceKitLSP/PlaygroundDiscovery.swift
@@ -28,9 +28,7 @@ extension SourceKitLSPServer {
     // playgrounds.
     await workspace.buildServerManager.waitForUpToDateBuildGraph()
 
-    let playgroundsFromSyntacticIndex = await languageServices.values.asyncFlatMap {
-      await $0.asyncFlatMap { await $0.syntacticPlaygrounds(in: workspace) }
-    }
+    let playgroundsFromSyntacticIndex = await workspace.syntacticIndex.playgrounds()
 
     // We don't need to sort the playgrounds here because they will get sorted by `workspacePlaygrounds` request handler
     return playgroundsFromSyntacticIndex
diff --git a/Sources/SourceKitLSP/SwiftSyntacticIndex.swift b/Sources/SourceKitLSP/SwiftSyntacticIndex.swift
index 13cdfaf9..134f6a1a 100644
--- a/Sources/SourceKitLSP/SwiftSyntacticIndex.swift
+++ b/Sources/SourceKitLSP/SwiftSyntacticIndex.swift
@@ -83,7 +83,7 @@ private struct IndexedSourceFile {
 ///
 /// The index does not get persisted to disk but instead gets rebuilt every time a workspace is opened (ie. usually when
 /// sourcekit-lsp is launched). Building it takes only a few seconds, even for large projects.
-package actor SwiftSyntacticIndex: BuildTargetListener, Sendable {
+package actor SwiftSyntacticIndex: Sendable {
   /// The tests discovered by the index.
   private var indexedSources: [DocumentURI: IndexedSourceFile] = [:]
 
@@ -104,20 +104,23 @@ package actor SwiftSyntacticIndex: BuildTargetListener, Sendable {
   /// Fetch the list of source files to scan for a given set of build targets
   private let determineFilesToScan: @Sendable (Set<BuildTargetIdentifier>?) async -> [DocumentURI]
 
-  // Syntactically parse tests from the given snapshot
-  private let syntacticTests: @Sendable (DocumentSnapshot) async -> [AnnotatedTestItem]
+  /// Syntactically parse tests from the given snapshot
+  private let syntacticTests: @Sendable (DocumentSnapshot, Workspace) async -> [AnnotatedTestItem]
 
-  // Syntactically parse playgrounds from the given snapshot
-  private let syntacticPlaygrounds: @Sendable (DocumentSnapshot) async -> [TextDocumentPlayground]
+  /// Syntactically parse playgrounds from the given snapshot
+  private let syntacticPlaygrounds: @Sendable (DocumentSnapshot, Workspace) async -> [TextDocumentPlayground]
 
   package init(
     determineFilesToScan: @Sendable @escaping (Set<BuildTargetIdentifier>?) async -> [DocumentURI],
-    syntacticTests: @Sendable @escaping (DocumentSnapshot) async -> [AnnotatedTestItem],
-    syntacticPlaygrounds: @Sendable @escaping (DocumentSnapshot) async -> [TextDocumentPlayground]
+    syntacticTests: @Sendable @escaping (DocumentSnapshot, Workspace) async -> [AnnotatedTestItem],
+    syntacticPlaygrounds: @Sendable @escaping (DocumentSnapshot, Workspace) async -> [TextDocumentPlayground]
   ) {
     self.determineFilesToScan = determineFilesToScan
     self.syntacticTests = syntacticTests
     self.syntacticPlaygrounds = syntacticPlaygrounds
+  }
+
+  func scan(workspace: Workspace) {
     indexingQueue.async(priority: .low, metadata: .initialPopulation) {
       let filesToScan = await self.determineFilesToScan(nil)
       // Divide the files into multiple batches. This is more efficient than spawning a new task for every file, mostly
@@ -128,7 +131,7 @@ package actor SwiftSyntacticIndex: BuildTargetListener, Sendable {
       let batches = filesToScan.partition(intoNumberOfBatches: ProcessInfo.processInfo.activeProcessorCount * 4)
       await batches.concurrentForEach { filesInBatch in
         for uri in filesInBatch {
-          await self.rescanFileAssumingOnQueue(uri)
+          await self.rescanFileAssumingOnQueue(uri, workspace)
         }
       }
     }
@@ -144,15 +147,15 @@ package actor SwiftSyntacticIndex: BuildTargetListener, Sendable {
   /// Called when the list of targets is updated.
   ///
   /// All files that are not in the new list of buildable files will be removed from the index.
-  package func buildTargetsChanged(_ changedTargets: Set<BuildTargetIdentifier>?) async {
+  package func buildTargetsChanged(_ changedTargets: Set<BuildTargetIdentifier>?, _ workspace: Workspace) async {
     let changedFiles = await determineFilesToScan(changedTargets)
     let removedFiles = Set(self.indexedSources.keys).subtracting(changedFiles)
     removeFilesFromIndex(removedFiles)
 
-    rescanFiles(changedFiles)
+    rescanFiles(changedFiles, workspace)
   }
 
-  package func filesDidChange(_ events: [FileEvent]) {
+  package func filesDidChange(_ events: [FileEvent], _ workspace: Workspace) {
     var removedFiles: Set<DocumentURI> = []
     var filesToRescan: [DocumentURI] = []
     for fileEvent in events {
@@ -168,11 +171,11 @@ package actor SwiftSyntacticIndex: BuildTargetListener, Sendable {
       }
     }
     removeFilesFromIndex(removedFiles)
-    rescanFiles(filesToRescan)
+    rescanFiles(filesToRescan, workspace)
   }
 
   /// Called when a list of files was updated. Re-scans those files
-  private func rescanFiles(_ uris: [DocumentURI]) {
+  private func rescanFiles(_ uris: [DocumentURI], _ workspace: Workspace) {
     // If we scan a file again, it might have been added after being removed before. Remove it from the list of removed
     // files.
     removedFiles.subtract(uris)
@@ -212,7 +215,7 @@ package actor SwiftSyntacticIndex: BuildTargetListener, Sendable {
     for batch in batches {
       self.indexingQueue.async(priority: .low, metadata: .index(Set(batch))) {
         for uri in batch {
-          await self.rescanFileAssumingOnQueue(uri)
+          await self.rescanFileAssumingOnQueue(uri, workspace)
         }
       }
     }
@@ -221,7 +224,7 @@ package actor SwiftSyntacticIndex: BuildTargetListener, Sendable {
   /// Re-scans a single file.
   ///
   /// - Important: This method must be called in a task that is executing on `indexingQueue`.
-  private func rescanFileAssumingOnQueue(_ uri: DocumentURI) async {
+  private func rescanFileAssumingOnQueue(_ uri: DocumentURI, _ workspace: Workspace) async {
     guard let url = uri.fileURL else {
       logger.log("Not indexing \(uri.forLogging) because it is not a file URL")
       return
@@ -254,10 +257,6 @@ package actor SwiftSyntacticIndex: BuildTargetListener, Sendable {
       return
     }
 
-    guard let url = uri.fileURL else {
-      logger.log("Not indexing \(uri.forLogging) because it is not a file URL")
-      return
-    }
     let snapshot: DocumentSnapshot? = orLog("Getting document snapshot for syntactic Swift scanning") {
       try DocumentSnapshot(withContentsFromDisk: url, language: .swift)
     }
@@ -265,7 +264,9 @@ package actor SwiftSyntacticIndex: BuildTargetListener, Sendable {
       return
     }
 
-    let (testItems, playgrounds) = await (syntacticTests(snapshot), syntacticPlaygrounds(snapshot))
+    let (testItems, playgrounds) = await (
+      syntacticTests(snapshot, workspace), syntacticPlaygrounds(snapshot, workspace)
+    )
 
     guard !removedFiles.contains(uri) else {
       // Check whether the file got removed while we were scanning it for tests. If so, don't add it back to
diff --git a/Sources/SourceKitLSP/TestDiscovery.swift b/Sources/SourceKitLSP/TestDiscovery.swift
index 90f3a90f..cf630153 100644
--- a/Sources/SourceKitLSP/TestDiscovery.swift
+++ b/Sources/SourceKitLSP/TestDiscovery.swift
@@ -245,9 +245,7 @@ extension SourceKitLSPServer {
 
     let semanticTestSymbolOccurrences = index?.unitTests().filter { return $0.canBeTestDefinition } ?? []
 
-    let testsFromSyntacticIndex = await languageServices.values.asyncFlatMap {
-      await $0.asyncFlatMap { await $0.syntacticTests(in: workspace) }
-    }
+    let testsFromSyntacticIndex = await workspace.syntacticIndex.tests()
     let testsFromSemanticIndex = testItems(
       for: semanticTestSymbolOccurrences,
       index: index,
diff --git a/Sources/SourceKitLSP/Workspace.swift b/Sources/SourceKitLSP/Workspace.swift
index a4a17bad..0ebcfa69 100644
--- a/Sources/SourceKitLSP/Workspace.swift
+++ b/Sources/SourceKitLSP/Workspace.swift
@@ -184,13 +184,12 @@ package final class Workspace: Sendable, BuildServerManagerDelegate {
     }
   }
 
+  /// The index that syntactically scans the workspace for Swift symbols.
+  let syntacticIndex: SwiftSyntacticIndex
+
   /// Language service for an open document, if available.
   private let languageServices: ThreadSafeBox<[DocumentURI: [any LanguageService]]> = ThreadSafeBox(initialValue: [:])
 
-  /// Build target listeners
-  private let buildTargetListeners: ThreadSafeBox<[ObjectIdentifier: BuildTargetListener]> = ThreadSafeBox(
-    initialValue: [:])
-
   /// The task that constructs the `SemanticIndexManager`, which keeps track of whose file's index is up-to-date in the
   /// workspace and schedules indexing and preparation tasks for files with out-of-date index.
   ///
@@ -261,6 +260,25 @@ package final class Workspace: Sendable, BuildServerManagerDelegate {
         return nil
       }
     }
+    // Trigger an initial population of `syntacticIndex`.
+    self.syntacticIndex = SwiftSyntacticIndex(
+      determineFilesToScan: { targets in
+        await orLog("Getting list of files for syntactic index population") {
+          try await buildServerManager.projectSourceFiles(in: targets)
+        } ?? []
+      },
+      syntacticTests: { (snapshot, workspace) in
+        await sourceKitLSPServer.languageServices(for: snapshot.uri, snapshot.language, in: workspace).asyncFlatMap {
+          await $0.syntacticTestItems(for: snapshot)
+        }
+      },
+      syntacticPlaygrounds: { (snapshot, workspace) in
+        await sourceKitLSPServer.languageServices(for: snapshot.uri, snapshot.language, in: workspace).asyncFlatMap {
+          await $0.syntacticPlaygrounds(for: snapshot, in: workspace)
+        }
+      }
+    )
+    await syntacticIndex.scan(workspace: self)
   }
 
   /// Creates a workspace for a given root `DocumentURI`, inferring the `ExternalWorkspace` if possible.
@@ -399,9 +417,9 @@ package final class Workspace: Sendable, BuildServerManagerDelegate {
     // Notify all clients about the reported and inferred edits.
     await buildServerManager.filesDidChange(events)
 
-    async let updateServer: Void? = await sourceKitLSPServer?.filesDidChange(events)
+    async let updateSyntacticIndex: Void = await syntacticIndex.filesDidChange(events, self)
     async let updateSemanticIndex: Void? = await semanticIndexManager?.filesDidChange(events)
-    _ = await (updateServer, updateSemanticIndex)
+    _ = await (updateSyntacticIndex, updateSemanticIndex)
   }
 
   /// The language services that can handle the given document. Callers should try to merge the results from the
@@ -464,26 +482,12 @@ package final class Workspace: Sendable, BuildServerManagerDelegate {
     await sourceKitLSPServer?.fileHandlingCapabilityChanged()
     await semanticIndexManager?.buildTargetsChanged(changedTargets)
     await orLog("Scheduling syntactic file re-indexing") {
-      _ = await buildTargetListeners.value.values.asyncMap {
-        await $0.buildTargetsChanged(changedTargets)
-      }
+      await syntacticIndex.buildTargetsChanged(changedTargets, self)
     }
 
     await scheduleUpdateOfUnitOutputPathsInIndexIfNecessary()
   }
 
-  package func addBuiltTargetListener(_ listener: any BuildTargetListener) {
-    buildTargetListeners.withLock {
-      $0[ObjectIdentifier(listener)] = listener
-    }
-  }
-
-  package func removeBuiltTargetListener(_ listener: any BuildTargetListener) {
-    buildTargetListeners.withLock {
-      $0[ObjectIdentifier(listener)] = nil
-    }
-  }
-
   private func scheduleUpdateOfUnitOutputPathsInIndexIfNecessary() async {
     indexUnitOutputPathsUpdateQueue.async {
       guard await self.uncheckedIndex?.usesExplicitOutputPaths ?? false else {
diff --git a/Sources/SwiftLanguageService/PlaygroundDiscovery.swift b/Sources/SwiftLanguageService/PlaygroundDiscovery.swift
index 4d445a9f..8329b3a1 100644
--- a/Sources/SwiftLanguageService/PlaygroundDiscovery.swift
+++ b/Sources/SwiftLanguageService/PlaygroundDiscovery.swift
@@ -13,24 +13,18 @@
 import BuildServerIntegration
 @_spi(SourceKitLSP) import BuildServerProtocol
 import Foundation
-@_spi(SourceKitLSP) import LanguageServerProtocol
+@_spi(SourceKitLSP) package import LanguageServerProtocol
 @_spi(SourceKitLSP) import SKLogging
 import SemanticIndex
-import SourceKitLSP
+package import SourceKitLSP
 import SwiftExtensions
-import ToolchainRegistry
 
 extension SwiftLanguageService {
-  static func syntacticPlaygrounds(
+  package func syntacticPlaygrounds(
     for snapshot: DocumentSnapshot,
-    in workspace: Workspace,
-    using syntaxTreeManager: SyntaxTreeManager,
-    toolchain: Toolchain
+    in workspace: Workspace
   ) async -> [TextDocumentPlayground] {
-    guard toolchain.swiftPlay != nil else {
-      return []
-    }
-    return await SwiftPlaygroundsScanner.findDocumentPlaygrounds(
+    await SwiftPlaygroundsScanner.findDocumentPlaygrounds(
       for: snapshot,
       workspace: workspace,
       syntaxTreeManager: syntaxTreeManager
diff --git a/Sources/SwiftLanguageService/SwiftLanguageService.swift b/Sources/SwiftLanguageService/SwiftLanguageService.swift
index d8011022..a82a5ffd 100644
--- a/Sources/SwiftLanguageService/SwiftLanguageService.swift
+++ b/Sources/SwiftLanguageService/SwiftLanguageService.swift
@@ -139,9 +139,6 @@ package actor SwiftLanguageService: LanguageService, Sendable {
   /// Shared syntax tree manager to share syntax trees when syntactically parsing different types
   let syntaxTreeManager: SyntaxTreeManager
 
-  /// The index that syntactically scans the workspace.
-  let syntacticIndex: SwiftSyntacticIndex
-
   /// Workspace this language service was created for
   let workspace: Workspace
 
@@ -279,27 +276,6 @@ package actor SwiftLanguageService: LanguageService, Sendable {
       clientHasDiagnosticsCodeDescriptionSupport: await capabilityRegistry.clientHasDiagnosticsCodeDescriptionSupport
     )
 
-    // Trigger an initial population of `syntacticIndex`.
-    self.syntacticIndex = SwiftSyntacticIndex(
-      determineFilesToScan: { targets in
-        await orLog("Getting list of files for syntactic index population") {
-          try await workspace.buildServerManager.projectSourceFiles(in: targets)
-        } ?? []
-      },
-      syntacticTests: {
-        await SwiftLanguageService.syntacticTestItems(for: $0, using: syntaxTreeManager)
-      },
-      syntacticPlaygrounds: {
-        await SwiftLanguageService.syntacticPlaygrounds(
-          for: $0,
-          in: workspace,
-          using: syntaxTreeManager,
-          toolchain: toolchain
-        )
-      }
-    )
-    workspace.addBuiltTargetListener(syntacticIndex)
-
     self.macroExpansionManager = MacroExpansionManager(swiftLanguageService: self)
     self.generatedInterfaceManager = GeneratedInterfaceManager(swiftLanguageService: self)
 
@@ -397,10 +373,6 @@ package actor SwiftLanguageService: LanguageService, Sendable {
   ) {
     self.stateChangeHandlers.append(handler)
   }
-
-  package func filesDidChange(_ events: [FileEvent]) async {
-    await syntacticIndex.filesDidChange(events)
-  }
 }
 
 extension SwiftLanguageService {
@@ -458,7 +430,6 @@ extension SwiftLanguageService {
   }
 
   package func shutdown() async {
-    self.workspace.removeBuiltTargetListener(syntacticIndex)
     await self.sourcekitd.removeNotificationHandler(self)
   }
 
@@ -1154,14 +1125,6 @@ extension SwiftLanguageService {
       )
     }
   }
-
-  package func syntacticTests(in workspace: Workspace) async -> [AnnotatedTestItem] {
-    await syntacticIndex.tests()
-  }
-
-  package func syntacticPlaygrounds(in workspace: Workspace) async -> [Playground] {
-    await syntacticIndex.playgrounds()
-  }
 }
 
 extension SwiftLanguageService: SKDNotificationHandler {
diff --git a/Sources/SwiftLanguageService/TestDiscovery.swift b/Sources/SwiftLanguageService/TestDiscovery.swift
index b18333cc..f645349b 100644
--- a/Sources/SwiftLanguageService/TestDiscovery.swift
+++ b/Sources/SwiftLanguageService/TestDiscovery.swift
@@ -52,9 +52,8 @@ extension SwiftLanguageService {
   /// Does not write the results to the index.
   ///
   /// The order of the returned tests is not defined. The results should be sorted before being returned to the editor.
-  static package func syntacticTestItems(
+  package func syntacticTestItems(
     for snapshot: DocumentSnapshot,
-    using syntaxTreeManager: SyntaxTreeManager
   ) async -> [AnnotatedTestItem] {
     async let swiftTestingTests = SyntacticSwiftTestingTestScanner.findTestSymbols(
       in: snapshot,