diff --git a/gns3server/db/models/llm_model_configs.py b/gns3server/db/models/llm_model_configs.py
index 2656ed83a..a7e5fe8ad 100644
--- a/gns3server/db/models/llm_model_configs.py
+++ b/gns3server/db/models/llm_model_configs.py
@@ -15,7 +15,7 @@
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
-from sqlalchemy import Column, Boolean, ForeignKey, CheckConstraint, UniqueConstraint, Index, Integer, String
+from sqlalchemy import Column, Boolean, ForeignKey, CheckConstraint, Index, Integer, String, text
 from sqlalchemy.dialects.postgresql import JSONB
 from sqlalchemy.orm import relationship
 
@@ -65,14 +65,12 @@ class LLMModelConfig(BaseTable):
             "model_type IN ('text', 'vision', 'stt', 'tts', 'multimodal', 'embedding', 'reranking', 'other')",
             name="valid_model_type_check"
         ),
-        # Each user can have at most one default config
-        UniqueConstraint("user_id", "is_default", name="unique_user_default",
-                         deferrable=True, initially="deferred",
-                         postgresql_where="is_default = TRUE AND user_id IS NOT NULL"),
-        # Each group can have at most one default config
-        UniqueConstraint("group_id", "is_default", name="unique_group_default",
-                         deferrable=True, initially="deferred",
-                         postgresql_where="is_default = TRUE AND group_id IS NOT NULL"),
+        # Each user can have at most one default config (partial unique index)
+        Index("unique_user_default", "user_id", unique=True,
+              postgresql_where=text("is_default = TRUE AND user_id IS NOT NULL")),
+        # Each group can have at most one default config (partial unique index)
+        Index("unique_group_default", "group_id", unique=True,
+              postgresql_where=text("is_default = TRUE AND group_id IS NOT NULL")),
         # Indexes for efficient queries
         Index("idx_llm_model_configs_user_id", "user_id"),
         Index("idx_llm_model_configs_group_id", "group_id"),
diff --git a/gns3server/db_migrations/versions/20260303_create_llm_model_configs_table.py b/gns3server/db_migrations/versions/20260303_create_llm_model_configs_table.py
index 007bde3b1..400c7482f 100644
--- a/gns3server/db_migrations/versions/20260303_create_llm_model_configs_table.py
+++ b/gns3server/db_migrations/versions/20260303_create_llm_model_configs_table.py
@@ -54,18 +54,6 @@ def upgrade() -> None:
             "model_type IN ('text', 'vision', 'stt', 'tts', 'multimodal', 'embedding', 'reranking', 'other')",
             name='valid_model_type_check'
         ),
-        sa.UniqueConstraint(
-            'user_id', 'is_default',
-            name='unique_user_default',
-            deferrable=True, initially='deferred',
-            postgresql_where=sa.text("is_default = TRUE AND user_id IS NOT NULL")
-        ),
-        sa.UniqueConstraint(
-            'group_id', 'is_default',
-            name='unique_group_default',
-            deferrable=True, initially='deferred',
-            postgresql_where=sa.text("is_default = TRUE AND group_id IS NOT NULL")
-        ),
     )
 
     # Create indexes for efficient queries
@@ -74,6 +62,20 @@ def upgrade() -> None:
     op.create_index('idx_llm_model_configs_model_type', 'llm_model_configs', ['model_type'])
     op.create_index('idx_llm_model_configs_config', 'llm_model_configs', ['config'], postgresql_using='gin')
 
+    # Create partial unique indexes for default configs
+    # Each user can have at most one default config
+    op.execute("""
+        CREATE UNIQUE INDEX unique_user_default
+        ON llm_model_configs (user_id)
+        WHERE is_default = TRUE AND user_id IS NOT NULL
+    """)
+    # Each group can have at most one default config
+    op.execute("""
+        CREATE UNIQUE INDEX unique_group_default
+        ON llm_model_configs (group_id)
+        WHERE is_default = TRUE AND group_id IS NOT NULL
+    """)
+
 
 def downgrade() -> None:
     # Drop indexes
@@ -81,6 +83,8 @@ def downgrade() -> None:
     op.drop_index('idx_llm_model_configs_model_type', table_name='llm_model_configs')
     op.drop_index('idx_llm_model_configs_group_id', table_name='llm_model_configs')
     op.drop_index('idx_llm_model_configs_user_id', table_name='llm_model_configs')
+    op.drop_index('unique_user_default', table_name='llm_model_configs')
+    op.drop_index('unique_group_default', table_name='llm_model_configs')
 
     # Drop table
     op.drop_table('llm_model_configs')
diff --git a/gns3server/schemas/__init__.py b/gns3server/schemas/__init__.py
index d04218f9b..9d1d54058 100644
--- a/gns3server/schemas/__init__.py
+++ b/gns3server/schemas/__init__.py
@@ -35,7 +35,6 @@ from .controller.llm_model_configs import (
     LLMModelConfigCreate,
     LLMModelConfigUpdate,
     LLMModelConfigResponse,
-    LLMModelConfigListResponse,
     LLMModelConfigWithSource,
     LLMModelConfigInheritedResponse
 )