diff --git a/mip-split.toml b/mip-split.toml
index 0d3f4004..d2540a4f 100644
--- a/mip-split.toml
+++ b/mip-split.toml
@@ -58,15 +58,19 @@ host-only = [
 ]
 
 [multimer]
-# `librt` is `timer_create` through ctypes/ffi, i.e. Linux. The asyncio pieces
-# (`_async_timer`, `_asyncio_loader`, `_mpasyncio`, `_schedule`) are portable and
-# stay with `machine`, `polling`, `_ticks` and `_core`.
+# The wake sources and the REPL hook that only a desktop, phone or browser
+# host can use: `_inputhook` (CPython's PyOS_InputHook), `_src_pending`
+# (CPython's worker thread + Py_AddPendingCall), `_src_signal` (POSIX timer
+# signals: CPython and unix MicroPython), `_src_native` (the windows port's
+# `_timing` helper) and `_src_wasm` (the browser). Boards keep the dispatcher,
+# `_hostloop`, `_repl`, `_ticks`, `_src_machine`, `_src_none`, `_src_asyncio`
+# and the asyncio loaders.
 host-only = [
-    "librt",
-    "sdl2",
-    "threading",
-    "wasm",
-    "win32",
+    "_inputhook",
+    "_src_native",
+    "_src_pending",
+    "_src_signal",
+    "_src_wasm",
 ]
 
 [bledev]
diff --git a/tests/test_mip_split.py b/tests/test_mip_split.py
new file mode 100644
index 00000000..3b275fb8
--- /dev/null
+++ b/tests/test_mip_split.py
@@ -0,0 +1,32 @@
+# SPDX-FileCopyrightText: 2026 Brad Barnett
+#
+# SPDX-License-Identifier: MIT
+"""mip-split.toml names only modules that exist under lib/.
+
+The MIP index sync refuses a release whose mip-split.toml names a module
+that isn't on disk, and it only runs after the tag exists (v0.6.0 failed
+that way, #103). This catches it in the pull request instead.
+"""
+
+import pathlib
+import tomllib
+import unittest
+
+ROOT = pathlib.Path(__file__).resolve().parent.parent
+
+
+class TestMipSplit(unittest.TestCase):
+    def test_host_only_names_exist(self):
+        split = tomllib.loads((ROOT / "mip-split.toml").read_text(encoding="utf-8"))
+        for package, section in split.items():
+            package_dir = ROOT / "lib" / package
+            with self.subTest(package=package):
+                self.assertTrue(package_dir.is_dir(), f"lib/{package} does not exist")
+                missing = sorted(
+                    name for name in section.get("host-only", ()) if not (package_dir / f"{name}.py").is_file()
+                )
+                self.assertEqual(missing, [], f"[{package}] host-only names modules that don't exist")
+
+
+if __name__ == "__main__":
+    unittest.main()