diff --git a/packages/razorback-plugin-dab/src/razorback_plugin_dab/generate/compose.py b/packages/razorback-plugin-dab/src/razorback_plugin_dab/generate/compose.py
index 9300245..24a7259 100644
--- a/packages/razorback-plugin-dab/src/razorback_plugin_dab/generate/compose.py
+++ b/packages/razorback-plugin-dab/src/razorback_plugin_dab/generate/compose.py
@@ -153,6 +153,13 @@ def generate_compose(
     main_service: dict[str, Any] = {
         "image": docker_image,
         "working_dir": container_workdir,
+        # Run as root. Harbor's codex runtime pre-creates root-owned
+        # /logs/agent and $CODEX_HOME during setup, then runs the agent as the
+        # image's default USER. dab-agent:latest ships USER exedev (non-root),
+        # so the agent cannot write those dirs and codex aborts with
+        # "Permission denied (os error 13)". ade-bench's images run as root and
+        # never hit this; pin main to root to match.
+        "user": "0:0",
         "networks": ["dab-net"] if networks_used else [],
     }
     if main_file_volumes:
diff --git a/packages/razorback-plugin-dab/tests/unit/test_compose_postgres.py b/packages/razorback-plugin-dab/tests/unit/test_compose_postgres.py
index bd6b4d1..b7d9975 100644
--- a/packages/razorback-plugin-dab/tests/unit/test_compose_postgres.py
+++ b/packages/razorback-plugin-dab/tests/unit/test_compose_postgres.py
@@ -63,6 +63,22 @@ def test_sqlite_does_not_spawn_service(tmp_path: Path):
     assert "dab-sqlite" not in compose["services"]
 
 
+def test_main_service_runs_as_root(tmp_path: Path):
+    # The codex runtime's setup (run as root) pre-creates root-owned
+    # /logs/agent and $CODEX_HOME, then harbor runs the agent as the image's
+    # default USER. dab-agent:latest is USER exedev (non-root), so the agent
+    # cannot write those dirs -> codex aborts with "Permission denied
+    # (os error 13)". Pin the main service to root so it can write them,
+    # matching the root images ade-bench runs successfully.
+    compose_text = generate_compose(
+        db_config=_BOOKREVIEW_LIKE,
+        dataset_name="bookreview",
+        data_root=tmp_path,
+    )
+    compose = yaml.safe_load(compose_text)
+    assert compose["services"]["main"]["user"] == "0:0"
+
+
 def test_dab_net_declared(tmp_path: Path):
     compose_text = generate_compose(
         db_config=_BOOKREVIEW_LIKE,