diff --git a/main/src/main/scala/sbt/internal/PluginDiscovery.scala b/main/src/main/scala/sbt/internal/PluginDiscovery.scala
index 934a0a53d..134768678 100644
--- a/main/src/main/scala/sbt/internal/PluginDiscovery.scala
+++ b/main/src/main/scala/sbt/internal/PluginDiscovery.scala
@@ -87,7 +87,10 @@ object PluginDiscovery:
       IO.delete(descriptor)
       None
     } else {
-      IO.writeLines(descriptor, names.distinct.sorted)
+      val lines = names.distinct.sorted
+      // Do not invalidate timestamp-based downstream caches when the descriptor content is unchanged.
+      if (!descriptor.exists || IO.readLines(descriptor) != lines)
+        IO.writeLines(descriptor, lines)
       Some(descriptor)
     }
   }
diff --git a/main/src/test/scala/sbt/internal/PluginDiscoveryTest.scala b/main/src/test/scala/sbt/internal/PluginDiscoveryTest.scala
new file mode 100644
index 000000000..db7c67877
--- /dev/null
+++ b/main/src/test/scala/sbt/internal/PluginDiscoveryTest.scala
@@ -0,0 +1,55 @@
+/*
+ * sbt
+ * Copyright 2023, Scala center
+ * Copyright 2011 - 2022, Lightbend, Inc.
+ * Copyright 2008 - 2010, Mark Harrah
+ * Licensed under Apache License 2.0 (see LICENSE)
+ */
+
+package sbt.internal
+
+import java.nio.file.Files
+import java.nio.file.attribute.FileTime
+
+import sbt.io.IO
+import verify.BasicTestSuite
+
+object PluginDiscoveryTest extends BasicTestSuite:
+  import PluginDiscovery.Paths.AutoPlugins
+
+  test("writeDescriptor preserves mtime when the descriptor content is unchanged"):
+    val directory = Files.createTempDirectory("plugin-discovery-test").toFile
+    try
+      val descriptor =
+        PluginDiscovery.writeDescriptor(Seq("example.B", "example.A"), directory, AutoPlugins).get
+      val expectedTime = FileTime.fromMillis(1234L)
+      Files.setLastModifiedTime(descriptor.toPath, expectedTime)
+
+      PluginDiscovery.writeDescriptor(
+        Seq("example.A", "example.B", "example.A"),
+        directory,
+        AutoPlugins
+      )
+
+      assert(Files.getLastModifiedTime(descriptor.toPath) == expectedTime)
+    finally IO.delete(directory)
+
+  test("writeDescriptor updates the descriptor when its content changes"):
+    val directory = Files.createTempDirectory("plugin-discovery-test").toFile
+    try
+      val descriptor = PluginDiscovery.writeDescriptor(Seq("example.A"), directory, AutoPlugins).get
+
+      PluginDiscovery.writeDescriptor(Seq("example.B"), directory, AutoPlugins)
+
+      assert(IO.readLines(descriptor) == Seq("example.B"))
+    finally IO.delete(directory)
+
+  test("writeDescriptor deletes the descriptor when no modules are discovered"):
+    val directory = Files.createTempDirectory("plugin-discovery-test").toFile
+    try
+      val descriptor = PluginDiscovery.writeDescriptor(Seq("example.A"), directory, AutoPlugins).get
+
+      assert(PluginDiscovery.writeDescriptor(Nil, directory, AutoPlugins).isEmpty)
+      assert(!descriptor.exists)
+    finally IO.delete(directory)
+end PluginDiscoveryTest
diff --git a/sbt-app/src/sbt-test/package/sbt-plugin-incremental/build.sbt b/sbt-app/src/sbt-test/package/sbt-plugin-incremental/build.sbt
new file mode 100644
index 000000000..c9f76a6f0
--- /dev/null
+++ b/sbt-app/src/sbt-test/package/sbt-plugin-incremental/build.sbt
@@ -0,0 +1,30 @@
+import java.nio.file.Files
+import java.nio.file.Paths
+
+sbtPlugin := true
+
+val recordPackageBinMtime = taskKey[Unit]("Records the packageBin output mtime")
+val checkPackageBinMtime = taskKey[Unit]("Checks that packageBin did not rewrite its output")
+val checkPackageBinRebuilt = taskKey[Unit]("Checks that packageBin rebuilt its output")
+
+recordPackageBinMtime := Def.uncached {
+  val artifact = fileConverter.value.toPath((Compile / packageBin / artifactPath).value)
+  val recordedMtime = Paths.get(System.getProperty("java.io.tmpdir"), s"package-bin-mtime-${baseDirectory.value.getAbsolutePath.hashCode}")
+  Files.writeString(recordedMtime, Files.getLastModifiedTime(artifact).toString)
+}
+
+checkPackageBinMtime := Def.uncached {
+  val artifact = fileConverter.value.toPath((Compile / packageBin / artifactPath).value)
+  val recordedMtime = Paths.get(System.getProperty("java.io.tmpdir"), s"package-bin-mtime-${baseDirectory.value.getAbsolutePath.hashCode}")
+  val expected = Files.readString(recordedMtime)
+  val actual = Files.getLastModifiedTime(artifact)
+  assert(actual.toString == expected, s"packageBin rewrote $artifact: $actual")
+}
+
+checkPackageBinRebuilt := Def.uncached {
+  val artifact = fileConverter.value.toPath((Compile / packageBin / artifactPath).value)
+  val recordedMtime = Paths.get(System.getProperty("java.io.tmpdir"), s"package-bin-mtime-${baseDirectory.value.getAbsolutePath.hashCode}")
+  val expected = Files.readString(recordedMtime)
+  val actual = Files.getLastModifiedTime(artifact)
+  assert(actual.toString != expected, s"packageBin did not rebuild $artifact")
+}
diff --git a/sbt-app/src/sbt-test/package/sbt-plugin-incremental/changes/AdditionalPlugin.scala b/sbt-app/src/sbt-test/package/sbt-plugin-incremental/changes/AdditionalPlugin.scala
new file mode 100644
index 000000000..5a29e69ba
--- /dev/null
+++ b/sbt-app/src/sbt-test/package/sbt-plugin-incremental/changes/AdditionalPlugin.scala
@@ -0,0 +1,5 @@
+package example
+
+import sbt.AutoPlugin
+
+object AdditionalPlugin extends AutoPlugin
diff --git a/sbt-app/src/sbt-test/package/sbt-plugin-incremental/src/main/scala/example/ExamplePlugin.scala b/sbt-app/src/sbt-test/package/sbt-plugin-incremental/src/main/scala/example/ExamplePlugin.scala
new file mode 100644
index 000000000..9f65abd01
--- /dev/null
+++ b/sbt-app/src/sbt-test/package/sbt-plugin-incremental/src/main/scala/example/ExamplePlugin.scala
@@ -0,0 +1,5 @@
+package example
+
+import sbt.AutoPlugin
+
+object ExamplePlugin extends AutoPlugin
diff --git a/sbt-app/src/sbt-test/package/sbt-plugin-incremental/test b/sbt-app/src/sbt-test/package/sbt-plugin-incremental/test
new file mode 100644
index 000000000..0e4f1acb5
--- /dev/null
+++ b/sbt-app/src/sbt-test/package/sbt-plugin-incremental/test
@@ -0,0 +1,8 @@
+> packageBin
+> recordPackageBinMtime
+> packageBin
+> checkPackageBinMtime
+
+$ copy-file changes/AdditionalPlugin.scala src/main/scala/example/AdditionalPlugin.scala
+> packageBin
+> checkPackageBinRebuilt
diff --git a/sbt-app/src/sbt-test/plugins/sbt-assembly/build.sbt b/sbt-app/src/sbt-test/plugins/sbt-assembly/build.sbt
new file mode 100644
index 000000000..6db649d51
--- /dev/null
+++ b/sbt-app/src/sbt-test/plugins/sbt-assembly/build.sbt
@@ -0,0 +1,57 @@
+import java.nio.file.Files
+import java.nio.file.Paths
+import java.nio.file.attribute.FileTime
+
+import sbtassembly.AssemblyPlugin.autoImport._
+
+val recordDescriptorMtime = taskKey[Unit]("Records the generated plugin descriptor mtime")
+val checkDescriptorMtime = taskKey[Unit]("Checks that assembly did not rewrite the generated plugin descriptor")
+val checkDescriptorRebuilt = taskKey[Unit]("Checks that assembly rewrote the generated plugin descriptor")
+val expectedAssemblyMtime = FileTime.fromMillis(1234L)
+val setAssemblyMtime = taskKey[Unit]("Sets the assembly output mtime")
+val checkAssemblyMtime = taskKey[Unit]("Checks that assembly did not rewrite its output")
+val checkAssemblyRebuilt = taskKey[Unit]("Checks that assembly rebuilt its output")
+
+sbtPlugin := true
+
+recordDescriptorMtime := Def.uncached {
+  val descriptor = (Compile / resourceManaged).value.toPath.resolve("sbt").resolve("sbt.autoplugins")
+  val recordedMtime =
+    Paths.get(System.getProperty("java.io.tmpdir"), s"plugin-descriptor-mtime-${baseDirectory.value.getAbsolutePath.hashCode}")
+  Files.writeString(recordedMtime, Files.getLastModifiedTime(descriptor).toString)
+}
+
+checkDescriptorMtime := Def.uncached {
+  val descriptor = (Compile / resourceManaged).value.toPath.resolve("sbt").resolve("sbt.autoplugins")
+  val recordedMtime =
+    Paths.get(System.getProperty("java.io.tmpdir"), s"plugin-descriptor-mtime-${baseDirectory.value.getAbsolutePath.hashCode}")
+  val expected = Files.readString(recordedMtime)
+  val actual = Files.getLastModifiedTime(descriptor)
+  assert(actual.toString == expected, s"assembly rewrote $descriptor: $actual")
+}
+
+checkDescriptorRebuilt := Def.uncached {
+  val descriptor = (Compile / resourceManaged).value.toPath.resolve("sbt").resolve("sbt.autoplugins")
+  val recordedMtime =
+    Paths.get(System.getProperty("java.io.tmpdir"), s"plugin-descriptor-mtime-${baseDirectory.value.getAbsolutePath.hashCode}")
+  val expected = Files.readString(recordedMtime)
+  val actual = Files.getLastModifiedTime(descriptor)
+  assert(actual.toString != expected, s"assembly did not rewrite $descriptor")
+}
+
+setAssemblyMtime := Def.uncached {
+  val artifact = (assembly / assemblyOutputPath).value
+  Files.setLastModifiedTime(artifact.toPath, expectedAssemblyMtime)
+}
+
+checkAssemblyMtime := Def.uncached {
+  val artifact = (assembly / assemblyOutputPath).value
+  val actual = Files.getLastModifiedTime(artifact.toPath)
+  assert(actual == expectedAssemblyMtime, s"assembly rewrote $artifact: $actual")
+}
+
+checkAssemblyRebuilt := Def.uncached {
+  val artifact = (assembly / assemblyOutputPath).value
+  val actual = Files.getLastModifiedTime(artifact.toPath)
+  assert(actual != expectedAssemblyMtime, s"assembly did not rebuild $artifact")
+}
diff --git a/sbt-app/src/sbt-test/plugins/sbt-assembly/changes/AdditionalPlugin.scala b/sbt-app/src/sbt-test/plugins/sbt-assembly/changes/AdditionalPlugin.scala
new file mode 100644
index 000000000..5a29e69ba
--- /dev/null
+++ b/sbt-app/src/sbt-test/plugins/sbt-assembly/changes/AdditionalPlugin.scala
@@ -0,0 +1,5 @@
+package example
+
+import sbt.AutoPlugin
+
+object AdditionalPlugin extends AutoPlugin
diff --git a/sbt-app/src/sbt-test/plugins/sbt-assembly/project/plugins.sbt b/sbt-app/src/sbt-test/plugins/sbt-assembly/project/plugins.sbt
new file mode 100644
index 000000000..a6be0fd1e
--- /dev/null
+++ b/sbt-app/src/sbt-test/plugins/sbt-assembly/project/plugins.sbt
@@ -0,0 +1 @@
+addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "2.4.2")
diff --git a/sbt-app/src/sbt-test/plugins/sbt-assembly/src/main/scala/example/ExamplePlugin.scala b/sbt-app/src/sbt-test/plugins/sbt-assembly/src/main/scala/example/ExamplePlugin.scala
new file mode 100644
index 000000000..9f65abd01
--- /dev/null
+++ b/sbt-app/src/sbt-test/plugins/sbt-assembly/src/main/scala/example/ExamplePlugin.scala
@@ -0,0 +1,5 @@
+package example
+
+import sbt.AutoPlugin
+
+object ExamplePlugin extends AutoPlugin
diff --git a/sbt-app/src/sbt-test/plugins/sbt-assembly/test b/sbt-app/src/sbt-test/plugins/sbt-assembly/test
new file mode 100644
index 000000000..2d6a4b2b4
--- /dev/null
+++ b/sbt-app/src/sbt-test/plugins/sbt-assembly/test
@@ -0,0 +1,11 @@
+> assembly
+> recordDescriptorMtime
+> setAssemblyMtime
+> assembly
+> checkDescriptorMtime
+> checkAssemblyMtime
+
+$ copy-file changes/AdditionalPlugin.scala src/main/scala/example/AdditionalPlugin.scala
+> assembly
+> checkDescriptorRebuilt
+> checkAssemblyRebuilt