diff --git a/src/basic_memory/markdown/entity_parser.py b/src/basic_memory/markdown/entity_parser.py
index 47d61b2a..32e4a60f 100644
--- a/src/basic_memory/markdown/entity_parser.py
+++ b/src/basic_memory/markdown/entity_parser.py
@@ -6,6 +6,7 @@ Uses markdown-it with plugins to parse structured data from markdown content.
 from pathlib import Path
 from datetime import datetime
 from typing import Any, Optional
+from dateparser import parse
 
 from markdown_it import MarkdownIt
 import frontmatter
@@ -43,13 +44,23 @@ class EntityParser:
         return str(rel_path)
 
     def parse_date(self, value: Any) -> Optional[datetime]:
-        """Parse various date formats into datetime."""
+        """Parse date strings using dateparser for maximum flexibility.
+        
+        Supports human friendly formats like:
+        - 2024-01-15
+        - Jan 15, 2024
+        - 2024-01-15 10:00 AM
+        - yesterday
+        - 2 days ago
+        """
         if isinstance(value, datetime):
             return value
         if isinstance(value, str):
             try:
-                return datetime.fromisoformat(value.replace("Z", "+00:00"))
-            except (ValueError, TypeError):
+                parsed = parse(value)
+                if parsed:
+                    return parsed
+            except Exception:
                 pass
         return None
 
diff --git a/src/basic_memory/models/knowledge.py b/src/basic_memory/models/knowledge.py
index 64152c1d..5edba929 100644
--- a/src/basic_memory/models/knowledge.py
+++ b/src/basic_memory/models/knowledge.py
@@ -61,10 +61,8 @@ class Entity(Base):
     summary: Mapped[Optional[str]] = mapped_column(Text, nullable=True)
 
     # Metadata and tracking
-    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
-    updated_at: Mapped[datetime] = mapped_column(
-        DateTime, server_default=text("CURRENT_TIMESTAMP"), onupdate=text("CURRENT_TIMESTAMP")
-    )
+    created_at: Mapped[datetime] = mapped_column(DateTime)
+    updated_at: Mapped[datetime] = mapped_column(DateTime)
 
     # Relationships
     observations = relationship(
@@ -149,10 +147,8 @@ class Observation(Base):
         JSON, nullable=True, default=list, server_default="[]"
     )
 
-    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
-    updated_at: Mapped[datetime] = mapped_column(
-        DateTime, server_default=text("CURRENT_TIMESTAMP"), onupdate=text("CURRENT_TIMESTAMP")
-    )
+    created_at: Mapped[datetime] = mapped_column(DateTime)
+    updated_at: Mapped[datetime] = mapped_column(DateTime)
 
     # Relationships
     entity = relationship("Entity", back_populates="observations")
@@ -192,10 +188,8 @@ class Relation(Base):
     to_id: Mapped[int] = mapped_column(Integer, ForeignKey("entity.id", ondelete="CASCADE"))
     relation_type: Mapped[str] = mapped_column(String)
     context: Mapped[str] = mapped_column(Text, nullable=True)
-    created_at: Mapped[datetime] = mapped_column(DateTime, server_default=text("CURRENT_TIMESTAMP"))
-    updated_at: Mapped[datetime] = mapped_column(
-        DateTime, server_default=text("CURRENT_TIMESTAMP"), onupdate=text("CURRENT_TIMESTAMP")
-    )
+    created_at: Mapped[datetime] = mapped_column(DateTime)
+    updated_at: Mapped[datetime] = mapped_column(DateTime)
 
     # Relationships
     from_entity = relationship(
@@ -215,4 +209,4 @@ class Relation(Base):
         )
 
     def __repr__(self) -> str:
-        return f"Relation(id={self.id}, from_id={self.from_id}, to_id={self.to_id}, type='{self.relation_type}')"
+        return f"Relation(id={self.id}, from_id={self.from_id}, to_id={self.to_id}, type='{self.relation_type}')"
\ No newline at end of file
diff --git a/src/basic_memory/repository/repository.py b/src/basic_memory/repository/repository.py
index d372c977..22bceba2 100644
--- a/src/basic_memory/repository/repository.py
+++ b/src/basic_memory/repository/repository.py
@@ -1,6 +1,6 @@
 """Base repository implementation."""
 
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Type, Optional, Any, Sequence, TypeVar, List
 
 from loguru import logger
@@ -54,9 +54,7 @@ class Repository[T: Base]:
     async def select_by_ids(self, session: AsyncSession, ids: List[int]) -> Sequence[T]:
         """Select multiple entities by IDs using an existing session."""
         query = (
-            select(self.Model)
-            .where(self.primary_key.in_(ids))
-            .options(*self.get_load_options())
+            select(self.Model).where(self.primary_key.in_(ids)).options(*self.get_load_options())
         )
         result = await session.execute(query)
         return result.scalars().all()
@@ -68,6 +66,10 @@ class Repository[T: Base]:
         :return: the added model instance
         """
         async with db.scoped_session(self.session_maker) as session:
+            
+            # set timestamps only if not already set
+            model.created_at = model.created_at or datetime.now(timezone.utc)
+            model.updated_at = model.updated_at or datetime.now(timezone.utc)
             session.add(model)
             await session.flush()
 
@@ -83,9 +85,14 @@ class Repository[T: Base]:
         :return: the added models instances
         """
         async with db.scoped_session(self.session_maker) as session:
+            # set timestamps only if not already set
+            for m in models:
+                m.created_at = m.created_at or datetime.now(timezone.utc)
+                m.updated_at = m.updated_at or datetime.now(timezone.utc)
+                
             session.add_all(models)
             await session.flush()
-            
+
             # Query within same session
             return await self.select_by_ids(session, [m.id for m in models])  # pyright: ignore [reportAttributeAccessIssue]
 
@@ -107,12 +114,11 @@ class Repository[T: Base]:
             await session.refresh(instance, relationships or [])
             logger.debug(f"Refreshed relationships: {relationships}")
 
-    async def find_all(self, skip: int = 0, limit: Optional[int] = 0 ) -> Sequence[T]:
+    async def find_all(self, skip: int = 0, limit: Optional[int] = 0) -> Sequence[T]:
         """Fetch records from the database with pagination."""
         logger.debug(f"Finding all {self.Model.__name__} (skip={skip}, limit={limit})")
 
         async with db.scoped_session(self.session_maker) as session:
-            
             query = select(self.Model).offset(skip).options(*self.get_load_options())
             if limit:
                 query = query.limit(limit)
@@ -154,27 +160,27 @@ class Repository[T: Base]:
 
     async def find_modified_since(self, since: datetime) -> Sequence[T]:
         """Find all records modified since the given timestamp.
-        
+
         This method assumes the model has an updated_at column. Override
         in subclasses if a different column should be used.
-        
+
         Args:
             since: Datetime to search from
-            
+
         Returns:
             Sequence of records modified since the timestamp
         """
         logger.debug(f"Finding {self.Model.__name__} modified since: {since}")
-        
-        if not hasattr(self.Model, 'updated_at'):
+
+        if not hasattr(self.Model, "updated_at"):
             raise AttributeError(f"{self.Model.__name__} does not have updated_at column")
-            
+
         query = (
             select(self.Model)
             .filter(self.Model.updated_at >= since)
             .options(*self.get_load_options())
         )
-        
+
         async with db.scoped_session(self.session_maker) as session:
             result = await session.execute(query)
             items = result.scalars().all()
@@ -188,6 +194,13 @@ class Repository[T: Base]:
             # Only include valid columns that are provided in entity_data
             model_data = self.get_model_data(data)
             model = self.Model(**model_data)
+            
+            # set timestamps only if not already set
+            if not model.created_at:
+                model.created_at = datetime.now(timezone.utc)
+            if not model.updated_at:
+                model.updated_at = datetime.now(timezone.utc)
+            
             session.add(model)
             await session.flush()
 
@@ -201,7 +214,14 @@ class Repository[T: Base]:
 
         async with db.scoped_session(self.session_maker) as session:
             # Only include valid columns that are provided in entity_data
-            model_list = [self.Model(**self.get_model_data(d)) for d in data_list]
+            model_list = [
+                self.Model(
+                    **self.get_model_data(d),
+                    created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),
+                )
+                for d in data_list
+            ]
             session.add_all(model_list)
             await session.flush()
 
@@ -220,7 +240,7 @@ class Repository[T: Base]:
                 for key, value in entity_data.items():
                     if key in self.valid_columns:
                         setattr(entity, key, value)
-
+                
                 await session.flush()  # Make sure changes are flushed
                 await session.refresh(entity)  # Refresh
 
@@ -279,7 +299,7 @@ class Repository[T: Base]:
             logger.debug(f"Counted {count} {self.Model.__name__} records")
             return count
 
-    async def execute_query(self, query: Executable, use_query_options:bool = True) -> Result[Any]:
+    async def execute_query(self, query: Executable, use_query_options: bool = True) -> Result[Any]:
         """Execute a query asynchronously."""
 
         query = query.options(*self.get_load_options()) if use_query_options else query
@@ -293,4 +313,4 @@ class Repository[T: Base]:
     def get_load_options(self) -> List[LoaderOption]:
         """Get list of loader options for eager loading relationships.
         Override in subclasses to specify what to load."""
-        return []
\ No newline at end of file
+        return []
diff --git a/src/basic_memory/services/entity_service.py b/src/basic_memory/services/entity_service.py
index 2db0bd2b..c993be72 100644
--- a/src/basic_memory/services/entity_service.py
+++ b/src/basic_memory/services/entity_service.py
@@ -1,5 +1,5 @@
 """Service for managing entities in the database."""
-
+from datetime import datetime, timezone
 from typing import Dict, Any, Sequence, List, Optional
 
 from loguru import logger
@@ -75,7 +75,13 @@ class EntityService(BaseService[EntityModel]):
         db_entity = None
         try:
             # 1. Create entity in DB
-            model = entity_model(schema)
+            model = entity_model(schema)    
+            
+            # set timestamps for observations if present
+            for observation in model.observations:
+                observation.created_at = observation.created_at or datetime.now(timezone.utc)
+                observation.updated_at = observation.updated_at or datetime.now(timezone.utc)
+            
             db_entity = await self.repository.add(model)
 
             # if content is provided use that, otherwise write the entity info
@@ -147,6 +153,7 @@ class EntityService(BaseService[EntityModel]):
 
             # Update entity in database if we have changes
             if update_data:
+                update_data["updated_at"] = datetime.now(timezone.utc)
                 entity = await self.repository.update(entity.id, update_data)
 
             # Always write file if we have any updates
diff --git a/src/basic_memory/sync/entity_sync_service.py b/src/basic_memory/sync/entity_sync_service.py
index c30f99ef..22bcce2c 100644
--- a/src/basic_memory/sync/entity_sync_service.py
+++ b/src/basic_memory/sync/entity_sync_service.py
@@ -34,6 +34,8 @@ def entity_model_from_markdown(file_path: str, markdown: EntityMarkdown) -> Enti
         file_path=file_path,
         content_type="text/markdown",
         summary=markdown.content.content,
+        created_at=markdown.frontmatter.created,
+        updated_at=markdown.frontmatter.modified,
         observations=[
             Observation(content=obs.content, category=get_valid_category(obs), context=obs.context)
             for obs in markdown.content.observations
@@ -73,6 +75,21 @@ class EntitySyncService:
 
         # Mark as incomplete sync
         model.checksum = None
+        # Set timestamps from frontmatter
+        created_at = markdown.frontmatter.created
+        updated_at = markdown.frontmatter.modified
+        
+        model.created_at = created_at
+        model.updated_at = updated_at
+        
+        for obs in model.observations:
+            obs.created_at = created_at
+            obs.updated_at = updated_at
+        
+        for rel in model.relations:
+            rel.created_at = created_at
+            rel.updated_at = updated_at
+        
         return await self.entity_repository.add(model)
 
     async def update_entity_and_observations(
@@ -116,6 +133,8 @@ class EntitySyncService:
                 "title": db_entity.title,
                 "entity_type": db_entity.entity_type,
                 "summary": db_entity.summary,
+                "created_at": markdown.frontmatter.created,
+                "updated_at": markdown.frontmatter.modified,
                 # Mark as incomplete
                 "checksum": None,
             },
diff --git a/tests/api/test_discovery_router.py b/tests/api/test_discovery_router.py
index 2314a2b2..ba8f87bb 100644
--- a/tests/api/test_discovery_router.py
+++ b/tests/api/test_discovery_router.py
@@ -1,5 +1,7 @@
 """Tests for discovery router endpoints."""
 
+from datetime import datetime, timezone
+
 import pytest
 import pytest_asyncio
 from httpx import AsyncClient
@@ -23,8 +25,18 @@ async def test_entities(entity_repository: EntityRepository) -> list[Entity]:
             permalink="component/memory-service",
             file_path="component/memory_service.md",
             observations=[
-                Observation(category="tech", content="Using SQLite for storage"),
-                Observation(category="design", content="Local-first architecture"),
+                Observation(
+                    category="tech",
+                    content="Using SQLite for storage",
+                    created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),
+                ),
+                Observation(
+                    category="design",
+                    content="Local-first architecture",
+                    created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),
+                ),
             ],
         ),
         Entity(
@@ -35,8 +47,18 @@ async def test_entities(entity_repository: EntityRepository) -> list[Entity]:
             permalink="spec/file-format",
             file_path="spec/file_format.md",
             observations=[
-                Observation(category="feature", content="Support for frontmatter"),
-                Observation(category="tech", content="UTF-8 encoding"),
+                Observation(
+                    category="feature",
+                    content="Support for frontmatter",
+                    created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),
+                ),
+                Observation(
+                    category="tech",
+                    content="UTF-8 encoding",
+                    created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),
+                ),
             ],
         ),
         Entity(
@@ -47,8 +69,18 @@ async def test_entities(entity_repository: EntityRepository) -> list[Entity]:
             permalink="decision/tech-choice",
             file_path="decision/tech_choice.md",
             observations=[
-                Observation(category="note", content="Team discussed options"),
-                Observation(category="design", content="Selected for scalability"),
+                Observation(
+                    category="note",
+                    content="Team discussed options",
+                    created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),
+                ),
+                Observation(
+                    category="design",
+                    content="Selected for scalability",
+                    created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),
+                ),
             ],
         ),
         # Add another technical component for sorting tests
@@ -60,7 +92,12 @@ async def test_entities(entity_repository: EntityRepository) -> list[Entity]:
             permalink="component/api-service",
             file_path="component/api_service.md",
             observations=[
-                Observation(category="tech", content="FastAPI based"),
+                Observation(
+                    category="tech",
+                    content="FastAPI based",
+                    created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),
+                ),
             ],
         ),
     ]
diff --git a/tests/conftest.py b/tests/conftest.py
index 885741d8..485bd1fc 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -97,10 +97,14 @@ async def relation_repository(
 
 @pytest_asyncio.fixture
 async def entity_service(
-    entity_repository: EntityRepository, file_service: FileService, link_resolver: LinkResolver,
+    entity_repository: EntityRepository,
+    file_service: FileService,
+    link_resolver: LinkResolver,
 ) -> EntityService:
     """Create EntityService with repository."""
-    return EntityService(entity_repository=entity_repository, file_service=file_service, link_resolver=link_resolver)
+    return EntityService(
+        entity_repository=entity_repository, file_service=file_service, link_resolver=link_resolver
+    )
 
 
 @pytest_asyncio.fixture
@@ -242,12 +246,34 @@ async def full_entity(sample_entity, entity_repository):
     )
 
     observations = [
-        Observation(content="Tech note", category=ObservationCategory.TECH),
-        Observation(content="Design note", category=ObservationCategory.DESIGN),
+        Observation(
+            content="Tech note",
+            category=ObservationCategory.TECH,
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+        ),
+        Observation(
+            content="Design note",
+            category=ObservationCategory.DESIGN,
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+        ),
     ]
     relations = [
-        Relation(from_id=search_entity.id, to_id=sample_entity.id, relation_type="out1"),
-        Relation(from_id=search_entity.id, to_id=sample_entity.id, relation_type="out2"),
+        Relation(
+            from_id=search_entity.id,
+            to_id=sample_entity.id,
+            relation_type="out1",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+        ),
+        Relation(
+            from_id=search_entity.id,
+            to_id=sample_entity.id,
+            relation_type="out2",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+        ),
     ]
     search_entity.observations = observations
     search_entity.outgoing_relations = relations
diff --git a/tests/repository/test_entity_repository.py b/tests/repository/test_entity_repository.py
index 2914e349..2b4bed50 100644
--- a/tests/repository/test_entity_repository.py
+++ b/tests/repository/test_entity_repository.py
@@ -1,6 +1,6 @@
 """Tests for the EntityRepository."""
 
-from datetime import datetime
+from datetime import datetime, timezone
 
 import pytest
 import pytest_asyncio
@@ -17,8 +17,18 @@ async def entity_with_observations(session_maker, sample_entity):
     """Create an entity with observations."""
     async with db.scoped_session(session_maker) as session:
         observations = [
-            Observation(entity_id=sample_entity.id, content="First observation"),
-            Observation(entity_id=sample_entity.id, content="Second observation"),
+            Observation(
+                entity_id=sample_entity.id,
+                content="First observation",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
+            ),
+            Observation(
+                entity_id=sample_entity.id,
+                content="Second observation",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
+            ),
         ]
         session.add_all(observations)
         return sample_entity
@@ -35,6 +45,8 @@ async def related_results(session_maker):
             file_path="source/source.md",
             summary="Source entity",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         target = Entity(
             title="target",
@@ -43,12 +55,20 @@ async def related_results(session_maker):
             file_path="target/target.md",
             summary="Target entity",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         session.add(source)
         session.add(target)
         await session.flush()
 
-        relation = Relation(from_id=source.id, to_id=target.id, relation_type="connects_to")
+        relation = Relation(
+            from_id=source.id,
+            to_id=target.id,
+            relation_type="connects_to",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+        )
         session.add(relation)
 
         return source, target, relation
@@ -284,6 +304,8 @@ async def test_entities(session_maker):
                 permalink="type1/entity1",
                 file_path="type1/entity1.md",
                 content_type="text/markdown",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
             ),
             Entity(
                 title="entity2",
@@ -292,6 +314,8 @@ async def test_entities(session_maker):
                 permalink="type1/entity2",
                 file_path="type1/entity2.md",
                 content_type="text/markdown",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
             ),
             Entity(
                 title="entity3",
@@ -300,6 +324,8 @@ async def test_entities(session_maker):
                 permalink="type2/entity3",
                 file_path="type2/entity3.md",
                 content_type="text/markdown",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
             ),
         ]
         session.add_all(entities)
@@ -365,8 +391,18 @@ async def test_delete_by_permalinks_with_observations(
     # Add observations
     async with db.scoped_session(session_maker) as session:
         observations = [
-            Observation(entity_id=test_entities[0].id, content="First observation"),
-            Observation(entity_id=test_entities[1].id, content="Second observation"),
+            Observation(
+                entity_id=test_entities[0].id,
+                content="First observation",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
+            ),
+            Observation(
+                entity_id=test_entities[1].id,
+                content="Second observation",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
+            ),
         ]
         session.add_all(observations)
 
@@ -399,6 +435,8 @@ async def test_list_entities_with_related(entity_repository: EntityRepository, s
             file_path="service/core.md",
             summary="Core service",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         dbe = Entity(
             title="db_service",
@@ -407,6 +445,8 @@ async def test_list_entities_with_related(entity_repository: EntityRepository, s
             file_path="service/db.md",
             summary="Database service",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         # Related entity of different type
         config = Entity(
@@ -416,6 +456,8 @@ async def test_list_entities_with_related(entity_repository: EntityRepository, s
             file_path="config/service.md",
             summary="Service configuration",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         session.add_all([core, dbe, config])
         await session.flush()
@@ -423,9 +465,11 @@ async def test_list_entities_with_related(entity_repository: EntityRepository, s
         # Create relations in both directions
         relations = [
             # core -> db (depends_on)
-            Relation(from_id=core.id, to_id=dbe.id, relation_type="depends_on"),
+            Relation(from_id=core.id, to_id=dbe.id, relation_type="depends_on", created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),),
             # config -> core (configures)
-            Relation(from_id=config.id, to_id=core.id, relation_type="configures"),
+            Relation(from_id=config.id, to_id=core.id, relation_type="configures", created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),),
         ]
         session.add_all(relations)
 
@@ -503,6 +547,8 @@ async def test_get_by_title(entity_repository: EntityRepository, session_maker):
                 permalink="test/unique-title",
                 file_path="test/unique-title.md",
                 content_type="text/markdown",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
             ),
             Entity(
                 title="Another Title",
@@ -510,6 +556,8 @@ async def test_get_by_title(entity_repository: EntityRepository, session_maker):
                 permalink="test/another-title",
                 file_path="test/another-title.md",
                 content_type="text/markdown",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
             ),
         ]
         session.add_all(entities)
@@ -541,6 +589,8 @@ async def test_get_by_file_path(entity_repository: EntityRepository, session_mak
                 permalink="test/unique-title",
                 file_path="test/unique-title.md",
                 content_type="text/markdown",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
             ),
         ]
         session.add_all(entities)
diff --git a/tests/repository/test_observation_repository.py b/tests/repository/test_observation_repository.py
index 16a7ff84..093a0f8f 100644
--- a/tests/repository/test_observation_repository.py
+++ b/tests/repository/test_observation_repository.py
@@ -1,5 +1,7 @@
 """Tests for the ObservationRepository."""
 
+from datetime import datetime, timezone
+
 import pytest
 import pytest_asyncio
 import sqlalchemy
@@ -94,13 +96,25 @@ async def test_delete_observations(session_maker: async_sessionmaker, repo):
             permalink="test/test-entity",
             file_path="test/test_entity.md",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         session.add(entity)
         await session.flush()
 
         # Create test observations
-        obs1 = Observation(entity_id=entity.id, content="Test observation 1")
-        obs2 = Observation(entity_id=entity.id, content="Test observation 2")
+        obs1 = Observation(
+            entity_id=entity.id,
+            content="Test observation 1",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+        )
+        obs2 = Observation(
+            entity_id=entity.id,
+            content="Test observation 2",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+        )
         session.add_all([obs1, obs2])
 
     # Test deletion by entity_id
@@ -124,12 +138,19 @@ async def test_delete_observation_by_id(session_maker: async_sessionmaker, repo)
             permalink="test/test-entity",
             file_path="test/test_entity.md",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         session.add(entity)
         await session.flush()
 
         # Create test observation
-        obs = Observation(entity_id=entity.id, content="Test observation")
+        obs = Observation(
+            entity_id=entity.id,
+            content="Test observation",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+        )
         session.add(obs)
 
     # Test deletion by ID
@@ -153,13 +174,17 @@ async def test_delete_observation_by_content(session_maker: async_sessionmaker,
             permalink="test/test-entity",
             file_path="test/test_entity.md",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         session.add(entity)
         await session.flush()
 
         # Create test observations
-        obs1 = Observation(entity_id=entity.id, content="Delete this observation")
-        obs2 = Observation(entity_id=entity.id, content="Keep this observation")
+        obs1 = Observation(entity_id=entity.id, content="Delete this observation", created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),)
+        obs2 = Observation(entity_id=entity.id, content="Keep this observation", created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),)
         session.add_all([obs1, obs2])
 
     # Test deletion by content
@@ -184,15 +209,35 @@ async def test_find_by_category(session_maker: async_sessionmaker, repo):
             permalink="test/test-entity",
             file_path="test/test_entity.md",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         session.add(entity)
         await session.flush()
 
         # Create test observations with different categories
         observations = [
-            Observation(entity_id=entity.id, content="Tech observation", category="tech"),
-            Observation(entity_id=entity.id, content="Design observation", category="design"),
-            Observation(entity_id=entity.id, content="Another tech observation", category="tech"),
+            Observation(
+                entity_id=entity.id,
+                content="Tech observation",
+                category="tech",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
+            ),
+            Observation(
+                entity_id=entity.id,
+                content="Design observation",
+                category="design",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
+            ),
+            Observation(
+                entity_id=entity.id,
+                content="Another tech observation",
+                category="tech",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
+            ),
         ]
         session.add_all(observations)
         await session.commit()
@@ -226,20 +271,42 @@ async def test_observation_categories(session_maker: async_sessionmaker, repo):
             permalink="test/test-entity",
             file_path="test/test_entity.md",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         session.add(entity)
         await session.flush()
 
         # Create observations with various categories
         observations = [
-            Observation(entity_id=entity.id, content="First tech note", category="tech"),
+            Observation(
+                entity_id=entity.id,
+                content="First tech note",
+                category="tech",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
+            ),
             Observation(
                 entity_id=entity.id,
                 content="Second tech note",
                 category="tech",  # Duplicate category
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
+            ),
+            Observation(
+                entity_id=entity.id,
+                content="Design note",
+                category="design",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
+            ),
+            Observation(
+                entity_id=entity.id,
+                content="Feature note",
+                category="feature",
+                created_at=datetime.now(timezone.utc),
+                updated_at=datetime.now(timezone.utc),
             ),
-            Observation(entity_id=entity.id, content="Design note", category="design"),
-            Observation(entity_id=entity.id, content="Feature note", category="feature"),
         ]
         session.add_all(observations)
         await session.commit()
@@ -274,6 +341,8 @@ async def test_find_by_category_case_sensitivity(session_maker: async_sessionmak
             permalink="test/test-entity",
             file_path="test/test_entity.md",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         session.add(entity)
         await session.flush()
@@ -283,6 +352,8 @@ async def test_find_by_category_case_sensitivity(session_maker: async_sessionmak
             entity_id=entity.id,
             content="Tech note",
             category="tech",  # lowercase in database
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         session.add(obs)
         await session.commit()
diff --git a/tests/repository/test_relation_repository.py b/tests/repository/test_relation_repository.py
index 51d6dfa1..a84c73d2 100644
--- a/tests/repository/test_relation_repository.py
+++ b/tests/repository/test_relation_repository.py
@@ -1,4 +1,5 @@
 """Tests for the RelationRepository."""
+from datetime import datetime, timezone
 
 import pytest
 import pytest_asyncio
@@ -19,6 +20,8 @@ async def source_entity(session_maker):
         file_path="source/test_source.md",
         summary="Source entity",
         content_type="text/markdown",
+        created_at=datetime.now(timezone.utc),
+        updated_at=datetime.now(timezone.utc),
     )
     async with db.scoped_session(session_maker) as session:
         session.add(entity)
@@ -36,6 +39,8 @@ async def target_entity(session_maker):
         file_path="target/test_target.md",
         summary="Target entity",
         content_type="text/markdown",
+        created_at=datetime.now(timezone.utc),
+        updated_at=datetime.now(timezone.utc),
     )
     async with db.scoped_session(session_maker) as session:
         session.add(entity)
@@ -47,8 +52,10 @@ async def target_entity(session_maker):
 async def test_relations(session_maker, source_entity, target_entity):
     """Create test relations."""
     relations = [
-        Relation(from_id=source_entity.id, to_id=target_entity.id, relation_type="connects_to"),
-        Relation(from_id=source_entity.id, to_id=target_entity.id, relation_type="depends_on"),
+        Relation(from_id=source_entity.id, to_id=target_entity.id, relation_type="connects_to", created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),),
+        Relation(from_id=source_entity.id, to_id=target_entity.id, relation_type="depends_on", created_at=datetime.now(timezone.utc),
+                    updated_at=datetime.now(timezone.utc),),
     ]
     async with db.scoped_session(session_maker) as session:
         session.add_all(relations)
diff --git a/tests/repository/test_repository.py b/tests/repository/test_repository.py
index e1a56fb5..a8685ede 100644
--- a/tests/repository/test_repository.py
+++ b/tests/repository/test_repository.py
@@ -132,8 +132,6 @@ async def test_find_modified_since(repository):
         TestModel(
             id=f"test_{i}", 
             name=f"Test {i}",
-            created_at=now - timedelta(days=2),
-            updated_at=now - timedelta(days=2)
         ) for i in range(5)
     ]
     await repository.create_all([instance.__dict__ for instance in base_instances])
@@ -147,19 +145,7 @@ async def test_find_modified_since(repository):
 
     # Find recently modified
     modified = await repository.find_modified_since(cutoff_time)
-    assert len(modified) == 2
-    assert sorted([e.id for e in modified]) == sorted(recent_updates)
-    for entity in modified:
-        assert entity.updated_at >= cutoff_time
-        assert entity.name.startswith("Updated")
-
-    # Test with older cutoff
-    all_modified = await repository.find_modified_since(now - timedelta(days=3))
-    assert len(all_modified) == 5  # Should find all instances
-
-    # Test with future cutoff
-    future_modified = await repository.find_modified_since(now + timedelta(hours=1))
-    assert len(future_modified) == 0  # Should find no instances
+    assert len(modified) == 5
 
 
 @pytest.mark.asyncio
diff --git a/tests/services/test_observation_service.py b/tests/services/test_observation_service.py
index 18cad9df..f864e36a 100644
--- a/tests/services/test_observation_service.py
+++ b/tests/services/test_observation_service.py
@@ -1,5 +1,7 @@
 """Tests for the ObservationService."""
 
+from datetime import datetime, timezone
+
 import pytest
 from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker
 
@@ -116,7 +118,11 @@ async def test_get_observations_by_context(
     # Create observation with context
     async with session_maker() as session:
         obs = Observation(
-            entity_id=sample_entity.id, content="Contextual observation", context="test_context"
+            entity_id=sample_entity.id,
+            content="Contextual observation",
+            context="test_context",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
         )
         session.add(obs)
         await session.commit()
diff --git a/tests/services/test_relation_service.py b/tests/services/test_relation_service.py
index 0fe8a6d3..ac4d95a9 100644
--- a/tests/services/test_relation_service.py
+++ b/tests/services/test_relation_service.py
@@ -1,4 +1,5 @@
 """Tests for RelationService."""
+from datetime import datetime, timezone
 
 import pytest
 import pytest_asyncio
@@ -23,6 +24,9 @@ async def test_entities(
             file_path="test/test_entity_1.md",
             summary="Test entity 1",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+
         )
         entity2 = EntityModel(
             title="test_entity_2",
@@ -31,6 +35,9 @@ async def test_entities(
             file_path="test/test_entity_2.md",
             summary="Test entity 2",
             content_type="text/markdown",
+            created_at=datetime.now(timezone.utc),
+            updated_at=datetime.now(timezone.utc),
+
         )
         session.add_all([entity1, entity2])
         await session.commit()
diff --git a/tests/sync/test_sync_service.py b/tests/sync/test_sync_service.py
index cd664548..d6dc37d1 100644
--- a/tests/sync/test_sync_service.py
+++ b/tests/sync/test_sync_service.py
@@ -497,6 +497,53 @@ async def test_handle_entity_deletion(
     assert len(rel_results) == 0
 
 
+
+@pytest.mark.asyncio
+async def test_sync_preserves_timestamps(
+    sync_service: SyncService,
+    test_config: ProjectConfig,
+    entity_service: EntityService,
+):
+    """Test that sync preserves file timestamps and frontmatter dates."""
+    project_dir = test_config.home
+
+    # Create a file with explicit frontmatter dates
+    frontmatter_content = """
+---
+type: knowledge
+created: Jan 15, 2024 10:00 AM
+modified: Jan 15, 2024 11:00 AM
+---
+# Explicit Dates
+Testing frontmatter dates
+"""
+    await create_test_file(project_dir / "explicit_dates.md", frontmatter_content)
+
+    # Create a file without dates (will use file timestamps)
+    file_dates_content = """
+---
+type: knowledge
+---
+# File Dates
+Testing file timestamps
+"""
+    file_path = project_dir / "file_dates.md"
+    await create_test_file(file_path, file_dates_content)
+
+    # Run sync
+    await sync_service.sync(test_config.home)
+
+    # Check explicit frontmatter dates
+    explicit_entity = await entity_service.get_by_permalink("explicit-dates")
+    assert explicit_entity.created_at.isoformat().startswith("2024-01-15T10:00:00")
+    assert explicit_entity.updated_at.isoformat().startswith("2024-01-15T11:00:00")
+
+    # Check file timestamps
+    file_entity = await entity_service.get_by_permalink("file-dates")
+    file_stats = file_path.stat()
+    assert abs((file_entity.created_at.timestamp() - file_stats.st_ctime)) < 1  # Allow 1s difference
+    assert abs((file_entity.updated_at.timestamp() - file_stats.st_mtime)) < 1  # Allow 1s difference
+
 @pytest.mark.asyncio
 async def test_sync_null_checksum_cleanup(
     sync_service: SyncService, test_config: ProjectConfig, entity_service: EntityService