diff --git a/packages/server/src/server/plugins/runtime.posix.test.ts b/packages/server/src/server/plugins/runtime.posix.test.ts
index 1792a9d7ff..ccaf00a332 100644
--- a/packages/server/src/server/plugins/runtime.posix.test.ts
+++ b/packages/server/src/server/plugins/runtime.posix.test.ts
@@ -1936,6 +1936,38 @@ export default function contribute(plugin: any) {
     );
   });
 
+  it("reports and removes a plugin it terminated for an invalid message", async () => {
+    const directory = await createPlugin(
+      "invalid-message",
+      `export default function contribute(plugin: unknown) {
+  void plugin;
+  setTimeout(() => process.send?.({ type: "not-a-plugin-message" }), 20);
+  return () => undefined;
+}`,
+    );
+    const sessions = createTrackedSessionHost();
+    const runtime = createTestRuntime({ sessionHost: sessions.host });
+    const exited = new Promise<string>((resolve) => {
+      runtime.subscribe((pluginId, error) => {
+        if (pluginId === "invalid-message" && error) resolve(error);
+      });
+    });
+    await runtime.startPlugin("invalid-message", directory);
+
+    // The runtime kills the process; it must then treat it like any other exited plugin.
+    await expect(exited).resolves.toBe("Plugin process exited: invalid-message");
+    expect(sessions.active.size).toBe(0);
+    expect(runtime.catalog()).toEqual([]);
+    expect(
+      pluginMessages(runtime, "invalid-message").some((message) =>
+        message.includes("sent an invalid message"),
+      ),
+    ).toBe(true);
+    await expect(runtime.invoke("invalid-message", "anything", {})).rejects.toThrow(
+      "Plugin is not available",
+    );
+  });
+
   it("re-attaches a plugin session when the daemon closes the socket under a live child", async () => {
     const directory = await createPlugin(
       "reattaching",
diff --git a/packages/server/src/server/plugins/runtime.ts b/packages/server/src/server/plugins/runtime.ts
index 98cbf8fcf0..f8fe8a91b5 100644
--- a/packages/server/src/server/plugins/runtime.ts
+++ b/packages/server/src/server/plugins/runtime.ts
@@ -247,8 +247,9 @@ function spawnPluginChild(): PluginChild {
   }) as PluginChild;
 }
 
+// Kill only. Node never emits "close" for a child whose IPC channel the parent disconnected, and
+// "close" is how the runtime learns that a plugin exited; the channel closes with the process.
 function terminatePluginChild(child: PluginChild): void {
-  if (child.connected) child.disconnect();
   if (!child.killed) child.kill();
 }