diff --git a/Sources/SourceKitLSPAPI/BuildDescription.swift b/Sources/SourceKitLSPAPI/BuildDescription.swift
index 5cdec76454f..af012d12802 100644
--- a/Sources/SourceKitLSPAPI/BuildDescription.swift
+++ b/Sources/SourceKitLSPAPI/BuildDescription.swift
@@ -22,21 +22,33 @@ import class Build.BuildPlan
 import class Build.ClangTargetBuildDescription
 import class Build.SwiftTargetBuildDescription
 import struct PackageGraph.ResolvedModule
+import struct PackageGraph.ModulesGraph
 
 public protocol BuildTarget {
     var sources: [URL] { get }
 
+    /// Whether the target is part of the root package that the user opened or if it's part of a package dependency.
+    var isPartOfRootPackage: Bool { get }
+
     func compileArguments(for fileURL: URL) throws -> [String]
- }
+}
+
+private struct WrappedClangTargetBuildDescription: BuildTarget {
+    private let description: ClangTargetBuildDescription
+    let isPartOfRootPackage: Bool
+
+    init(description: ClangTargetBuildDescription, isPartOfRootPackage: Bool) {
+        self.description = description
+        self.isPartOfRootPackage = isPartOfRootPackage
+    }
 
-extension ClangTargetBuildDescription: BuildTarget {
     public var sources: [URL] {
-        return (try? compilePaths().map { URL(fileURLWithPath: $0.source.pathString) }) ?? []
+        return (try? description.compilePaths().map { URL(fileURLWithPath: $0.source.pathString) }) ?? []
     }
 
     public func compileArguments(for fileURL: URL) throws -> [String] {
         let filePath = try resolveSymlinks(try AbsolutePath(validating: fileURL.path))
-        let commandLine = try self.emitCommandLine(for: filePath)
+        let commandLine = try description.emitCommandLine(for: filePath)
         // First element on the command line is the compiler itself, not an argument.
         return Array(commandLine.dropFirst())
     }
@@ -44,9 +56,11 @@ extension ClangTargetBuildDescription: BuildTarget {
 
 private struct WrappedSwiftTargetBuildDescription: BuildTarget {
     private let description: SwiftTargetBuildDescription
+    let isPartOfRootPackage: Bool
 
-    init(description: SwiftTargetBuildDescription) {
+    init(description: SwiftTargetBuildDescription, isPartOfRootPackage: Bool) {
         self.description = description
+        self.isPartOfRootPackage = isPartOfRootPackage
     }
 
     var sources: [URL] {
@@ -71,17 +85,27 @@ public struct BuildDescription {
     }
 
     // FIXME: should not use `ResolvedTarget` in the public interface
-    public func getBuildTarget(for target: ResolvedModule) -> BuildTarget? {
+    public func getBuildTarget(for target: ResolvedModule, in modulesGraph: ModulesGraph) -> BuildTarget? {
         if let description = buildPlan.targetMap[target.id] {
             switch description {
             case .clang(let description):
-                return description
+                return WrappedClangTargetBuildDescription(
+                    description: description,
+                    isPartOfRootPackage: modulesGraph.rootPackages.map(\.id).contains(description.package.id)
+                )
             case .swift(let description):
-                return WrappedSwiftTargetBuildDescription(description: description)
+                return WrappedSwiftTargetBuildDescription(
+                    description: description,
+                    isPartOfRootPackage: modulesGraph.rootPackages.map(\.id).contains(description.package.id)
+                )
             }
         } else {
             if target.type == .plugin, let package = self.buildPlan.graph.package(for: target) {
-                return PluginTargetBuildDescription(target: target, toolsVersion: package.manifest.toolsVersion)
+                return PluginTargetBuildDescription(
+                    target: target,
+                    toolsVersion: package.manifest.toolsVersion,
+                    isPartOfRootPackage: modulesGraph.rootPackages.map(\.id).contains(package.id)
+                )
             }
             return nil
         }
diff --git a/Sources/SourceKitLSPAPI/PluginTargetBuildDescription.swift b/Sources/SourceKitLSPAPI/PluginTargetBuildDescription.swift
index 9fc7403baba..8e6a147cc3e 100644
--- a/Sources/SourceKitLSPAPI/PluginTargetBuildDescription.swift
+++ b/Sources/SourceKitLSPAPI/PluginTargetBuildDescription.swift
@@ -21,11 +21,13 @@ private import class PackageModel.UserToolchain
 struct PluginTargetBuildDescription: BuildTarget {
     private let target: ResolvedModule
     private let toolsVersion: ToolsVersion
+    let isPartOfRootPackage: Bool
 
-    init(target: ResolvedModule, toolsVersion: ToolsVersion) {
+    init(target: ResolvedModule, toolsVersion: ToolsVersion, isPartOfRootPackage: Bool) {
         assert(target.type == .plugin)
         self.target = target
         self.toolsVersion = toolsVersion
+        self.isPartOfRootPackage = isPartOfRootPackage
     }
 
     var sources: [URL] {
diff --git a/Tests/SourceKitLSPAPITests/SourceKitLSPAPITests.swift b/Tests/SourceKitLSPAPITests/SourceKitLSPAPITests.swift
index 0ef54fbc308..92b275bab08 100644
--- a/Tests/SourceKitLSPAPITests/SourceKitLSPAPITests.swift
+++ b/Tests/SourceKitLSPAPITests/SourceKitLSPAPITests.swift
@@ -63,7 +63,8 @@ class SourceKitLSPAPITests: XCTestCase {
                 "-emit-dependencies",
                 "-emit-module",
                 "-emit-module-path", "/path/to/build/\(buildParameters.triple)/debug/exe.build/exe.swiftmodule"
-            ]
+            ],
+            isPartOfRootPackage: true
         )
         try description.checkArguments(
             for: "lib",
@@ -73,7 +74,8 @@ class SourceKitLSPAPITests: XCTestCase {
                 "-emit-dependencies",
                 "-emit-module",
                 "-emit-module-path", "/path/to/build/\(buildParameters.triple)/debug/Modules/lib.swiftmodule"
-            ]
+            ],
+            isPartOfRootPackage: true
         )
     }
 }
@@ -82,10 +84,11 @@ extension SourceKitLSPAPI.BuildDescription {
     @discardableResult func checkArguments(
         for targetName: String,
         graph: ModulesGraph,
-        partialArguments: [String]
+        partialArguments: [String],
+        isPartOfRootPackage: Bool
     ) throws -> Bool {
         let target = try XCTUnwrap(graph.allTargets.first(where: { $0.name == targetName }))
-        let buildTarget = try XCTUnwrap(self.getBuildTarget(for: target))
+        let buildTarget = try XCTUnwrap(self.getBuildTarget(for: target, in: graph))
 
         guard let file = buildTarget.sources.first else {
             XCTFail("build target \(targetName) contains no files")
@@ -96,6 +99,7 @@ extension SourceKitLSPAPI.BuildDescription {
         let result = arguments.contains(partialArguments)
 
         XCTAssertTrue(result, "could not match \(partialArguments) to actual arguments \(arguments)")
+        XCTAssertEqual(buildTarget.isPartOfRootPackage, isPartOfRootPackage)
         return result
     }
 }