diff --git a/deploy/files/usr/local/lib/systemd/system/left4me-server@.service b/deploy/files/usr/local/lib/systemd/system/left4me-server@.service
index d5d4698..e6f5d4f 100644
--- a/deploy/files/usr/local/lib/systemd/system/left4me-server@.service
+++ b/deploy/files/usr/local/lib/systemd/system/left4me-server@.service
@@ -33,7 +33,13 @@ WorkingDirectory=-/var/lib/left4me/runtime/%i/merged/left4dead2
 # anyway. ExecStopPost (not ExecStop) so unmount runs after the cgroup is
 # cleared; ExecStop runs while srcds is still alive and would EBUSY.
 ExecStartPre=+/usr/local/libexec/left4me/left4me-overlay mount %i
-ExecStart=/var/lib/left4me/installation/srcds_run -game left4dead2 +hostport ${L4D2_PORT} $L4D2_ARGS
+# Run from the merged overlay, NOT installation/. srcds_run is a shell
+# script that `cd`s to its own dirname before exec'ing srcds_linux, so the
+# binary's path determines where the engine reads gameinfo.txt and addons
+# from — WorkingDirectory has no effect. Invoking installation/srcds_run
+# would resolve everything against the lower layer and never see overlay-
+# provided plugins (Metamod/SourceMod) or cfgs (zonemod, confogl).
+ExecStart=/var/lib/left4me/runtime/%i/merged/srcds_run -game left4dead2 +hostport ${L4D2_PORT} $L4D2_ARGS
 ExecStopPost=+/usr/local/libexec/left4me/left4me-overlay umount %i
 Restart=on-failure
 RestartSec=5
diff --git a/deploy/tests/test_deploy_artifacts.py b/deploy/tests/test_deploy_artifacts.py
index d870893..09fe5ce 100644
--- a/deploy/tests/test_deploy_artifacts.py
+++ b/deploy/tests/test_deploy_artifacts.py
@@ -67,7 +67,11 @@ def test_server_unit_contains_required_runtime_contract():
     # mount helper before the merged dir exists. ExecStart re-applies and
     # finds the dir once the mount has landed.
     assert "WorkingDirectory=-/var/lib/left4me/runtime/%i/merged/left4dead2" in unit
-    assert "ExecStart=/var/lib/left4me/installation/srcds_run" in unit
+    # ExecStart must invoke srcds_run from the *merged* overlay tree, not
+    # from installation/. srcds_run cds to its own dirname; if we point at
+    # installation/, the engine reads gameinfo.txt and addons from the lower
+    # layer and never sees overlay plugins (Metamod/SourceMod) or cfgs.
+    assert "ExecStart=/var/lib/left4me/runtime/%i/merged/srcds_run" in unit
     assert "$L4D2_ARGS" in unit
     assert "${L4D2_ARGS}" not in unit
     assert "NoNewPrivileges=true" in unit