diff --git a/src/autointent/_optimization_config.py b/src/autointent/_optimization_config.py
index 547474a92..64767c7bd 100644
--- a/src/autointent/_optimization_config.py
+++ b/src/autointent/_optimization_config.py
@@ -2,7 +2,7 @@
 
 from typing import TYPE_CHECKING, Any
 
-from pydantic import BaseModel, Field, PositiveInt, field_validator
+from pydantic import BaseModel, Field, NonNegativeInt, field_validator
 
 from .configs import (
     CrossEncoderConfig,
@@ -49,7 +49,7 @@ def validate_embedder_config(cls, v: Any) -> EmbedderConfig:  # noqa: ANN401
 
     hpo_config: HPOConfig = HPOConfig()
 
-    seed: PositiveInt = 42
+    seed: NonNegativeInt = 42
 
     @classmethod
     def from_preset(cls, preset: SearchSpacePreset) -> OptimizationConfig:
diff --git a/tests/configs/test_full_config.py b/tests/configs/test_full_config.py
index b95b4a63f..02f732204 100644
--- a/tests/configs/test_full_config.py
+++ b/tests/configs/test_full_config.py
@@ -17,3 +17,13 @@ def test_not_valid_reporting() -> None:
 
     with pytest.raises(ValidationError):
         OptimizationConfig(**config)
+
+
+def test_optimization_config_accepts_seed_zero() -> None:
+    config = OptimizationConfig(seed=0, search_space=[])
+    assert config.seed == 0
+
+
+def test_optimization_config_rejects_negative_seed() -> None:
+    with pytest.raises(ValidationError):
+        OptimizationConfig(seed=-1, search_space=[])