diff --git a/Sources/ScipioKit/Producer/Cache/CacheSystem.swift b/Sources/ScipioKit/Producer/Cache/CacheSystem.swift
index 33d5ee0..a3842ec 100644
--- a/Sources/ScipioKit/Producer/Cache/CacheSystem.swift
+++ b/Sources/ScipioKit/Producer/Cache/CacheSystem.swift
@@ -96,9 +96,10 @@ extension PinsStore.PinState: @retroactive Hashable {
 }
 
 public struct SwiftPMCacheKey: CacheKey {
-    public var canonicalPackageLocation: String
-    public var targetName: String
+    /// The canonical repository URL the manifest was loaded from, for local packages only.
+    public var localPackageCanonicalLocation: String?
     public var pin: PinsStore.PinState
+    public var targetName: String
     var buildOptions: BuildOptions
     public var clangVersion: String
     public var xcodeVersion: XcodeVersion
@@ -231,9 +232,18 @@ struct CacheSystem: Sendable {
     }
 
     func calculateCacheKey(of target: CacheTarget) async throws -> SwiftPMCacheKey {
-        let canonicalPackageLocation = target.buildProduct.package.manifest.canonicalPackageLocation
+        let package = target.buildProduct.package
+
+        let localPackageCanonicalLocation: String? = switch package.manifest.packageKind {
+        case .fileSystem, .localSourceControl:
+            package.manifest.canonicalPackageLocation.description
+        case .root, .remoteSourceControl, .registry:
+            nil
+        }
+
+        let pin = try retrievePin(package: package)
+
         let targetName = target.buildProduct.target.name
-        let pin = try retrievePin(package: target.buildProduct.package)
         let buildOptions = target.buildOptions
         guard let clangVersion = try await ClangChecker().fetchClangVersion() else {
             throw Error.compilerVersionNotDetected
@@ -242,9 +252,9 @@ struct CacheSystem: Sendable {
             throw Error.xcodeVersionNotDetected
         }
         return SwiftPMCacheKey(
-            canonicalPackageLocation: canonicalPackageLocation.description,
-            targetName: targetName,
+            localPackageCanonicalLocation: localPackageCanonicalLocation,
             pin: pin.state,
+            targetName: targetName,
             buildOptions: buildOptions,
             clangVersion: clangVersion,
             xcodeVersion: xcodeVersion,
diff --git a/Tests/ScipioKitTests/CacheSystemTests.swift b/Tests/ScipioKitTests/CacheSystemTests.swift
index 4a632da..55a7a4b 100644
--- a/Tests/ScipioKitTests/CacheSystemTests.swift
+++ b/Tests/ScipioKitTests/CacheSystemTests.swift
@@ -2,6 +2,7 @@ import Foundation
 @testable import ScipioKit
 import XCTest
 import Basics
+import struct PackageModel.CanonicalPackageLocation
 
 private let fixturePath = URL(fileURLWithPath: #filePath)
     .deletingLastPathComponent()
@@ -19,9 +20,9 @@ final class CacheSystemTests: XCTestCase {
 
     func testEncodeCacheKey() throws {
         let cacheKey = SwiftPMCacheKey(
-            canonicalPackageLocation: "/path/to/MyPackage",
-            targetName: "MyTarget",
+            localPackageCanonicalLocation: "/path/to/MyPackage",
             pin: .revision("111111111"),
+            targetName: "MyTarget",
             buildOptions: .init(
                 buildConfiguration: .release,
                 isDebugSymbolsEmbedded: false,
@@ -64,7 +65,7 @@ final class CacheSystemTests: XCTestCase {
               "iOS"
             ]
           },
-          "canonicalPackageLocation" : "\\/path\\/to\\/MyPackage",
+          "localPackageCanonicalLocation" : "\\/path\\/to\\/MyPackage",
           "clangVersion" : "clang-1400.0.29.102",
           "pin" : {
             "revision" : "111111111"
@@ -147,7 +148,11 @@ final class CacheSystemTests: XCTestCase {
         let scipioTestingRemote = try await scipioTestingCacheKey(fixture: "AsRemotePackage")
         let scipioTestingLocal = try await scipioTestingCacheKey(fixture: "AsLocalPackage")
 
-        XCTAssertNotEqual(scipioTestingRemote.canonicalPackageLocation, scipioTestingLocal.canonicalPackageLocation)
+        XCTAssertNil(scipioTestingRemote.localPackageCanonicalLocation)
+        XCTAssertEqual(
+            scipioTestingLocal.localPackageCanonicalLocation,
+            CanonicalPackageLocation(tempDir.appending(component: "scipio-testing").pathString).description
+        )
         XCTAssertEqual(scipioTestingRemote.targetName, scipioTestingLocal.targetName)
         XCTAssertEqual(scipioTestingRemote.pin, scipioTestingLocal.pin)
     }