diff --git a/.github/workflows/publish-runtime.yml b/.github/workflows/publish-runtime.yml
index c22fbcc7..b7c77f82 100644
--- a/.github/workflows/publish-runtime.yml
+++ b/.github/workflows/publish-runtime.yml
@@ -142,7 +142,14 @@ jobs:
           # of \`from molecule_runtime.transcript_auth import ...\` — the
           # 0.1.16 incident), this fails with ModuleNotFoundError instead
           # of shipping to PyPI and breaking every workspace startup.
-          import molecule_runtime.main  # noqa: F401
+          # Import the entry-point target by NAME — not just the module.
+          # The wheel's pyproject.toml declares
+          # `molecule-runtime = molecule_runtime.main:main_sync` so if
+          # main_sync goes missing (it did in 0.1.16-0.1.18), every
+          # workspace startup fails with `ImportError: cannot import name
+          # 'main_sync'`. Plain `import molecule_runtime.main` doesn't
+          # catch that because the module loads fine.
+          from molecule_runtime.main import main_sync  # noqa: F401
           from molecule_runtime import a2a_client, a2a_tools
           from molecule_runtime.builtin_tools import memory
           from molecule_runtime.adapters import get_adapter, BaseAdapter, AdapterConfig
diff --git a/workspace/main.py b/workspace/main.py
index 2dd9d4e4..a947123c 100644
--- a/workspace/main.py
+++ b/workspace/main.py
@@ -613,5 +613,18 @@ async def main():  # pragma: no cover
         await temporal_wrapper.stop()
 
 
-if __name__ == "__main__":  # pragma: no cover
+def main_sync():  # pragma: no cover
+    """Synchronous entry point for the `molecule-runtime` console script.
+
+    Declared in scripts/build_runtime_package.py as the wheel's entry-point
+    target (`molecule-runtime = "molecule_runtime.main:main_sync"`). Removed
+    silently during the pre-monorepo consolidation, which broke every
+    workspace startup against 0.1.16/0.1.17/0.1.18 with `ImportError:
+    cannot import name 'main_sync'`. The .github/workflows/runtime-pin-compat.yml
+    smoke step is the regression gate.
+    """
     asyncio.run(main())
+
+
+if __name__ == "__main__":  # pragma: no cover
+    main_sync()