diff --git a/skaha/models.py b/skaha/models.py
index ab66cc7..9f41b53 100644
--- a/skaha/models.py
+++ b/skaha/models.py
@@ -45,7 +45,7 @@ class CreateSpec(BaseModel):
         None, description="Arguments to the command.", examples=["-la"]
     )
     env: Optional[Dict[str, Any]] = Field(
-        ..., description="Environment variables.", examples=[{"FOO": "BAR"}]
+        None, description="Environment variables.", examples=[{"FOO": "BAR"}]
     )
     replicas: int = Field(
         1, description="Number of sessions to launch.", ge=1, le=256, exclude=True
diff --git a/uv.lock b/uv.lock
index a2da75e..3577d9a 100644
--- a/uv.lock
+++ b/uv.lock
@@ -1532,7 +1532,7 @@ wheels = [
 
 [[package]]
 name = "skaha"
-version = "1.4.1"
+version = "1.4.2"
 source = { virtual = "." }
 dependencies = [
     { name = "click" },