diff --git a/dimos/core/coordination/test_worker.py b/dimos/core/coordination/test_worker.py
index c606dcda73..a9708fc845 100644
--- a/dimos/core/coordination/test_worker.py
+++ b/dimos/core/coordination/test_worker.py
@@ -14,14 +14,16 @@
 
 from typing import TYPE_CHECKING
 
+from pydantic import Field
 import pytest
 
-from dimos.core.coordination.worker_manager_python import WorkerManagerPython
+from dimos.core.coordination.worker_manager_python import WorkerManagerPython, _merge_config_kwargs
 from dimos.core.core import rpc
 from dimos.core.global_config import GlobalConfig, global_config
-from dimos.core.module import Module
+from dimos.core.module import Module, ModuleConfig
 from dimos.core.stream import In, Out
 from dimos.msgs.geometry_msgs.Vector3 import Vector3
+from dimos.protocol.service.spec import BaseConfig
 
 if TYPE_CHECKING:
     from dimos.core.resource_monitor.stats import WorkerStats
@@ -81,6 +83,15 @@ def get_multiplier(self) -> int:
         return self.multiplier
 
 
+class NestedConfig(BaseConfig):
+    a: int = 0
+    b: int = 2
+
+
+class ModuleWithNestedConfig(ModuleConfig):
+    sub: NestedConfig = Field(default_factory=lambda: NestedConfig(a=10, b=20))
+
+
 class HeavyModule(Module):
     dedicated_worker = True
 
@@ -189,6 +200,17 @@ def test_worker_manager_parallel_deployment(create_worker_manager):
     module3.stop()
 
 
+def test_nested_blueprint_config_defaults_survive_cli_override():
+    blueprint_kwargs = {"sub": NestedConfig(a=10, b=20)}
+    cli_kwargs = {"sub": {"a": "1"}}
+
+    merged = _merge_config_kwargs(blueprint_kwargs, cli_kwargs)
+    config = ModuleWithNestedConfig(**merged)
+
+    assert config.sub.a == 1
+    assert config.sub.b == 20
+
+
 @pytest.mark.skipif_macos_bug
 def test_collect_stats(create_worker_manager):
     from dimos.core.resource_monitor.monitor import StatsMonitor
diff --git a/dimos/core/coordination/worker_manager_python.py b/dimos/core/coordination/worker_manager_python.py
index 4963db2dac..2956dff71a 100644
--- a/dimos/core/coordination/worker_manager_python.py
+++ b/dimos/core/coordination/worker_manager_python.py
@@ -17,6 +17,8 @@
 from collections.abc import Iterable, Mapping
 from typing import TYPE_CHECKING, Any
 
+from pydantic import BaseModel
+
 from dimos.core.coordination.python_worker import PythonWorker
 from dimos.core.global_config import GlobalConfig
 from dimos.core.module import ModuleBase, ModuleSpec
@@ -30,6 +32,26 @@
 logger = setup_logger()
 
 
+def _merge_config_kwargs(base: Mapping[str, Any], overrides: Mapping[str, Any]) -> dict[str, Any]:
+    merged = dict(base)
+    for key, override_value in overrides.items():
+        merged[key] = _merge_config_value(merged.get(key), override_value)
+    return merged
+
+
+def _merge_config_value(base_value: Any, override_value: Any) -> Any:
+    if not isinstance(override_value, Mapping):
+        return override_value
+
+    if isinstance(base_value, BaseModel):
+        base_value = base_value.model_dump(mode="python")
+
+    if not isinstance(base_value, Mapping):
+        return dict(override_value)
+
+    return _merge_config_kwargs(base_value, override_value)
+
+
 class WorkerManagerPython:
     deployment_identifier: str = "python"
 
@@ -161,7 +183,11 @@ def deploy_parallel(
             module_class, _, kwargs = specs[i]
             worker = self._select_worker(dedicated=module_class.dedicated_worker)
             worker.reserve_slot()
-            kwargs.update(blueprint_args.get(module_class.name, {}))
+            specs[i] = (
+                specs[i][0],
+                specs[i][1],
+                _merge_config_kwargs(kwargs, blueprint_args.get(module_class.name, {})),
+            )
             workers_by_index[i] = worker
 
         assignments = [(workers_by_index[i], specs[i]) for i in range(len(specs))]