diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/wm/ex/ProjectFrameTypeServiceTest.kt b/platform/platform-tests/testSrc/com/intellij/openapi/wm/ex/ProjectFrameTypeServiceTest.kt
new file mode 100644
index 000000000000..5a70401ca111
--- /dev/null
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/wm/ex/ProjectFrameTypeServiceTest.kt
@@ -0,0 +1,148 @@
+// Copyright 2000-2026 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
+package com.intellij.openapi.wm.ex
+
+import com.intellij.openapi.actionSystem.ActionPlaces
+import com.intellij.openapi.util.JDOMUtil
+import com.intellij.testFramework.ApplicationRule
+import com.intellij.testFramework.DisposableRule
+import com.intellij.testFramework.ExtensionTestUtil
+import com.intellij.testFramework.LoggedErrorProcessor
+import com.intellij.util.xmlb.XmlSerializer
+import org.assertj.core.api.Assertions.assertThat
+import org.junit.ClassRule
+import org.junit.Rule
+import org.junit.Test
+
+class ProjectFrameTypeServiceTest {
+  companion object {
+    @ClassRule
+    @JvmField
+    val appRule = ApplicationRule()
+  }
+
+  @Rule
+  @JvmField
+  val disposableRule = DisposableRule()
+
+  @Test
+  fun `descriptor deserializes plugin xml notation`() {
+    val bean = XmlSerializer.deserialize(
+      JDOMUtil.load("""
+        <projectFrameType id="AGENT_DEDICATED" reopenWhenHidden="true" toolWindowLayoutProfile="air.dedicated">
+          <excludeAction place="MainToolbar" id="MainToolbarVCSGroup"/>
+          <excludeAction place="MainToolbar" id="NewUiRunWidget"/>
+        </projectFrameType>
+      """.trimIndent()),
+      ProjectFrameTypeBean::class.java,
+    )
+
+    assertThat(bean.id).isEqualTo("AGENT_DEDICATED")
+    assertThat(bean.reopenWhenHidden).isTrue()
+    assertThat(bean.toolWindowLayoutProfile).isEqualTo("air.dedicated")
+    assertThat(bean.excludedActions.map { it.place to it.actionId })
+      .containsExactly("MainToolbar" to "MainToolbarVCSGroup", "MainToolbar" to "NewUiRunWidget")
+  }
+
+  @Test
+  fun `descriptor defaults are inert`() {
+    val bean = XmlSerializer.deserialize(JDOMUtil.load("""<projectFrameType id="BARE"/>"""), ProjectFrameTypeBean::class.java)
+
+    assertThat(bean.reopenWhenHidden).isFalse()
+    assertThat(bean.toolWindowLayoutProfile).isNull()
+    assertThat(bean.excludedActions).isEmpty()
+  }
+
+  @Test
+  fun `policy is resolved by frame type id`() {
+    val service = maskDescriptors(
+      descriptor("DEDICATED") {
+        reopenWhenHidden = true
+        toolWindowLayoutProfile = "dedicated"
+        excludedActions = listOf(
+          exclusion(ActionPlaces.MAIN_TOOLBAR, "MainToolbarVCSGroup"),
+          exclusion(ActionPlaces.MAIN_TOOLBAR, "NewUiRunWidget"),
+          exclusion("OtherPlace", "SomethingElse"),
+        )
+      },
+      descriptor("PLAIN"),
+    )
+
+    assertThat(service.findDescriptor("DEDICATED")?.id).isEqualTo("DEDICATED")
+    assertThat(service.canReopenWhenHidden("DEDICATED")).isTrue()
+    assertThat(service.getToolWindowLayoutProfileId("DEDICATED")).isEqualTo("dedicated")
+    assertThat(service.getExcludedActionIds("DEDICATED", ActionPlaces.MAIN_TOOLBAR))
+      .containsExactly("MainToolbarVCSGroup", "NewUiRunWidget")
+
+    assertThat(service.canReopenWhenHidden("PLAIN")).isFalse()
+    assertThat(service.getToolWindowLayoutProfileId("PLAIN")).isNull()
+    assertThat(service.getExcludedActionIds("PLAIN", ActionPlaces.MAIN_TOOLBAR)).isEmpty()
+  }
+
+  @Test
+  fun `undeclared and blank frame types resolve to no policy`() {
+    val service = maskDescriptors(descriptor("DEDICATED") { reopenWhenHidden = true })
+
+    for (frameTypeId in listOf(null, "", "   ", "UNKNOWN")) {
+      assertThat(service.findDescriptor(frameTypeId)).describedAs(frameTypeId ?: "null").isNull()
+      assertThat(service.canReopenWhenHidden(frameTypeId)).describedAs(frameTypeId ?: "null").isFalse()
+      assertThat(service.getToolWindowLayoutProfileId(frameTypeId)).describedAs(frameTypeId ?: "null").isNull()
+      assertThat(service.getExcludedActionIds(frameTypeId, ActionPlaces.MAIN_TOOLBAR)).describedAs(frameTypeId ?: "null").isEmpty()
+    }
+  }
+
+  @Test
+  fun `declared keys are trimmed and blanks are dropped`() {
+    val service = maskDescriptors(
+      descriptor("  DEDICATED  ") {
+        toolWindowLayoutProfile = "  dedicated  "
+        excludedActions = listOf(
+          exclusion("  ${ActionPlaces.MAIN_TOOLBAR}  ", "  MainToolbarVCSGroup  "),
+          exclusion(ActionPlaces.MAIN_TOOLBAR, "   "),
+        )
+      }
+    )
+
+    assertThat(service.getToolWindowLayoutProfileId("DEDICATED")).isEqualTo("dedicated")
+    assertThat(service.getExcludedActionIds("  DEDICATED  ", ActionPlaces.MAIN_TOOLBAR)).containsExactly("MainToolbarVCSGroup")
+    assertThat(service.getExcludedActionIds("DEDICATED", "  ")).isEmpty()
+  }
+
+  @Test
+  fun `duplicate ids keep the first descriptor and report the clash`() {
+    val service = maskDescriptors(
+      descriptor("DEDICATED") { toolWindowLayoutProfile = "first" },
+      descriptor("DEDICATED") { toolWindowLayoutProfile = "second" },
+    )
+
+    val loggedErrors = ArrayList<String>()
+    LoggedErrorProcessor.executeWith<RuntimeException>(object : LoggedErrorProcessor() {
+      override fun processError(category: String, message: String, details: Array<String?>, t: Throwable?): MutableSet<Action?> {
+        loggedErrors.add(message)
+        return Action.NONE
+      }
+    }) {
+      assertThat(service.getToolWindowLayoutProfileId("DEDICATED")).isEqualTo("first")
+    }
+
+    assertThat(loggedErrors).singleElement().asString().contains("DEDICATED")
+  }
+
+  private fun maskDescriptors(vararg beans: ProjectFrameTypeBean): ProjectFrameTypeService {
+    ExtensionTestUtil.maskExtensions(ProjectFrameTypeService.EP_NAME, beans.toList(), disposableRule.disposable)
+    return ProjectFrameTypeService()
+  }
+}
+
+private fun descriptor(id: String, configure: ProjectFrameTypeBean.() -> Unit = {}): ProjectFrameTypeBean {
+  return ProjectFrameTypeBean().also {
+    it.id = id
+    it.configure()
+  }
+}
+
+private fun exclusion(place: String, actionId: String): ProjectFrameActionExclusionBean {
+  return ProjectFrameActionExclusionBean().also {
+    it.place = place
+    it.actionId = actionId
+  }
+}