diff --git a/Sources/ScipioKit/BuildOptions.swift b/Sources/ScipioKit/BuildOptions.swift
index 87b3cf81..0eee5af2 100644
--- a/Sources/ScipioKit/BuildOptions.swift
+++ b/Sources/ScipioKit/BuildOptions.swift
@@ -1,7 +1,9 @@
 import Foundation
 import OrderedCollections
+import Basics
 
 struct BuildOptions: Hashable, Codable, Sendable {
+
     init(
         buildConfiguration: BuildConfiguration,
         isDebugSymbolsEmbedded: Bool,
diff --git a/Sources/ScipioKit/Producer/FrameworkProducer.swift b/Sources/ScipioKit/Producer/FrameworkProducer.swift
index 4cfcf3d1..3b3c7c9f 100644
--- a/Sources/ScipioKit/Producer/FrameworkProducer.swift
+++ b/Sources/ScipioKit/Producer/FrameworkProducer.swift
@@ -14,6 +14,7 @@ struct FrameworkProducer {
     private let overwrite: Bool
     private let outputDir: URL
     private let fileSystem: any FileSystem
+    private let toolchainEnvironment: [String: String]?
 
     private var cacheStorage: (any CacheStorage)? {
         switch cacheMode {
@@ -51,6 +52,7 @@ struct FrameworkProducer {
         cacheMode: Runner.Options.CacheMode,
         overwrite: Bool,
         outputDir: URL,
+        toolchainEnvironment: [String: String]? = nil,
         fileSystem: any FileSystem = localFileSystem
     ) {
         self.descriptionPackage = descriptionPackage
@@ -59,6 +61,7 @@ struct FrameworkProducer {
         self.cacheMode = cacheMode
         self.overwrite = overwrite
         self.outputDir = outputDir
+        self.toolchainEnvironment = toolchainEnvironment
         self.fileSystem = fileSystem
     }
 
diff --git a/Sources/ScipioKit/Producer/PIF/PIFCompiler.swift b/Sources/ScipioKit/Producer/PIF/PIFCompiler.swift
index edf2fe35..bae94f27 100644
--- a/Sources/ScipioKit/Producer/PIF/PIFCompiler.swift
+++ b/Sources/ScipioKit/Producer/PIF/PIFCompiler.swift
@@ -10,6 +10,7 @@ struct PIFCompiler: Compiler {
     private let fileSystem: any FileSystem
     private let executor: any Executor
     private let buildOptionsMatrix: [String: BuildOptions]
+    private let toolchainEnvironment: [String: String]?
 
     private let buildParametersGenerator: BuildParametersGenerator
 
@@ -17,12 +18,14 @@ struct PIFCompiler: Compiler {
         descriptionPackage: DescriptionPackage,
         buildOptions: BuildOptions,
         buildOptionsMatrix: [String: BuildOptions],
+        toolchainEnvironment: [String: String]? = nil,
         fileSystem: any FileSystem = TSCBasic.localFileSystem,
         executor: any Executor = ProcessExecutor()
     ) {
         self.descriptionPackage = descriptionPackage
         self.buildOptions = buildOptions
         self.buildOptionsMatrix = buildOptionsMatrix
+        self.toolchainEnvironment = toolchainEnvironment
         self.fileSystem = fileSystem
         self.executor = executor
         self.buildParametersGenerator = .init(buildOptions: buildOptions, fileSystem: fileSystem)
@@ -30,7 +33,7 @@ struct PIFCompiler: Compiler {
 
     private func fetchDefaultToolchainBinPath() async throws -> AbsolutePath {
         let result = try await executor.execute("/usr/bin/xcrun", "xcode-select", "-p")
-        let rawString = try result.unwrapOutput()
+        let rawString = try result.unwrapOutput().trimmingCharacters(in: .whitespacesAndNewlines)
         let developerDirPath = try AbsolutePath(validating: rawString)
         let toolchainPath = try RelativePath(validating: "./Toolchains/XcodeDefault.xctoolchain/usr/bin")
         return developerDirPath.appending(toolchainPath)
@@ -38,7 +41,7 @@ struct PIFCompiler: Compiler {
 
     private func makeToolchain(for sdk: SDK) async throws -> UserToolchain {
         let toolchainDirPath = try await fetchDefaultToolchainBinPath()
-        let toolchainGenerator = ToolchainGenerator(toolchainDirPath: toolchainDirPath)
+        let toolchainGenerator = ToolchainGenerator(toolchainDirPath: toolchainDirPath, environment: toolchainEnvironment)
         return try await toolchainGenerator.makeToolChain(sdk: sdk)
     }
 
diff --git a/Sources/ScipioKit/Producer/PIF/ToolchainGenerator.swift b/Sources/ScipioKit/Producer/PIF/ToolchainGenerator.swift
index d1e0d262..6a048093 100644
--- a/Sources/ScipioKit/Producer/PIF/ToolchainGenerator.swift
+++ b/Sources/ScipioKit/Producer/PIF/ToolchainGenerator.swift
@@ -2,6 +2,7 @@ import Foundation
 import TSCUtility
 #if compiler(>=6.0)
 @_spi(SwiftPMInternal) import PackageModel
+@_spi(SwiftPMInternal) import struct Basics.Environment
 #else
 import PackageModel
 #endif
@@ -10,16 +11,27 @@ import struct Basics.Triple
 
 struct ToolchainGenerator {
     private let toolchainDirPath: AbsolutePath
+    private let environment: [String: String]?
     private let executor: any Executor
 
-    init(toolchainDirPath: AbsolutePath, executor: any Executor = ProcessExecutor()) {
+    init(
+        toolchainDirPath: AbsolutePath,
+        environment: [String: String]? = nil,
+        executor: any Executor = ProcessExecutor()
+    ) {
         self.toolchainDirPath = toolchainDirPath
+        self.environment = environment
         self.executor = executor
     }
 
     func makeToolChain(sdk: SDK) async throws -> UserToolchain {
         let destination: SwiftSDK = try await makeDestination(sdk: sdk)
-        #if swift(>=5.10)
+        #if compiler(>=6.0)
+        return try UserToolchain(
+            swiftSDK: destination,
+            environment: environment.map(Environment.init) ?? .current
+        )
+        #elseif swift(>=5.10)
         return try UserToolchain(swiftSDK: destination)
         #else
         return try UserToolchain(destination: destination)
diff --git a/Sources/ScipioKit/Runner.swift b/Sources/ScipioKit/Runner.swift
index 436971c8..22294061 100644
--- a/Sources/ScipioKit/Runner.swift
+++ b/Sources/ScipioKit/Runner.swift
@@ -234,6 +234,7 @@ extension Runner {
         public var cacheMode: CacheMode
         public var overwrite: Bool
         public var verbose: Bool
+        public var toolchainEnvironment: [String: String]?
 
         public init(
             baseBuildOptions: BuildOptions = .init(),
@@ -241,7 +242,8 @@ extension Runner {
             shouldOnlyUseVersionsFromResolvedFile: Bool = false,
             cacheMode: CacheMode = .project,
             overwrite: Bool = false,
-            verbose: Bool = false
+            verbose: Bool = false,
+            toolchainEnvironment: [String: String]? = nil
         ) {
             self.buildOptionsContainer = BuildOptionsContainer(
                 baseBuildOptions: baseBuildOptions,
@@ -251,6 +253,7 @@ extension Runner {
             self.cacheMode = cacheMode
             self.overwrite = overwrite
             self.verbose = verbose
+            self.toolchainEnvironment = toolchainEnvironment
         }
     }
 }