diff --git a/backend/adapter_processor_v2/models.py b/backend/adapter_processor_v2/models.py
index 13be07cdc0..a6fab0c1f9 100644
--- a/backend/adapter_processor_v2/models.py
+++ b/backend/adapter_processor_v2/models.py
@@ -10,7 +10,7 @@
 from django.db.models import QuerySet
 from tenant_account_v2.models import OrganizationMember
 from utils.exceptions import InvalidEncryptionKey
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.models.organization_mixin import (
     DefaultOrganizationManagerMixin,
     DefaultOrganizationMixin,
@@ -29,7 +29,7 @@
 logger = logging.getLogger(__name__)
 
 
-class AdapterInstanceModelManager(DefaultOrganizationManagerMixin, models.Manager):
+class AdapterInstanceModelManager(DefaultOrganizationManagerMixin, BaseModelManager):
     def get_queryset(self) -> QuerySet[Any]:
         return super().get_queryset()
 
diff --git a/backend/api_v2/models.py b/backend/api_v2/models.py
index 532b67d2dc..cc19902bde 100644
--- a/backend/api_v2/models.py
+++ b/backend/api_v2/models.py
@@ -7,7 +7,7 @@
 from django.db.models.signals import post_delete
 from django.dispatch import receiver
 from pipeline_v2.models import Pipeline
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.models.organization_mixin import (
     DefaultOrganizationManagerMixin,
     DefaultOrganizationMixin,
@@ -24,7 +24,7 @@
 API_ENDPOINT_MAX_LENGTH = 255
 
 
-class APIDeploymentModelManager(DefaultOrganizationManagerMixin, models.Manager):
+class APIDeploymentModelManager(DefaultOrganizationManagerMixin, BaseModelManager):
     def for_user(self, user):
         """Filter API deployments that the user can access:
         - API deployments created by the user
diff --git a/backend/connector_v2/models.py b/backend/connector_v2/models.py
index c3d0e6108b..73ea38b57c 100644
--- a/backend/connector_v2/models.py
+++ b/backend/connector_v2/models.py
@@ -8,7 +8,7 @@
 from connector_processor.constants import ConnectorKeys
 from django.db import models
 from utils.fields import EncryptedBinaryField
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.models.organization_mixin import (
     DefaultOrganizationManagerMixin,
     DefaultOrganizationMixin,
@@ -22,7 +22,7 @@
 logger = logging.getLogger(__name__)
 
 
-class ConnectorInstanceModelManager(DefaultOrganizationManagerMixin, models.Manager):
+class ConnectorInstanceModelManager(DefaultOrganizationManagerMixin, BaseModelManager):
     def get_queryset(self) -> models.QuerySet:
         return super().get_queryset()
 
diff --git a/backend/dashboard_metrics/management/commands/backfill_metrics.py b/backend/dashboard_metrics/management/commands/backfill_metrics.py
index daf0b3130e..9c4d82baca 100644
--- a/backend/dashboard_metrics/management/commands/backfill_metrics.py
+++ b/backend/dashboard_metrics/management/commands/backfill_metrics.py
@@ -424,7 +424,7 @@ def _bulk_upsert_hourly(self, aggregations: dict) -> int:
                 "project",
                 "tag",
             ],
-            update_fields=["metric_type", "metric_value", "metric_count", "modified_at"],
+            update_fields=["metric_type", "metric_value", "metric_count"],
         )
         return len(objects)
 
@@ -457,7 +457,7 @@ def _bulk_upsert_daily(self, aggregations: dict) -> int:
                 "project",
                 "tag",
             ],
-            update_fields=["metric_type", "metric_value", "metric_count", "modified_at"],
+            update_fields=["metric_type", "metric_value", "metric_count"],
         )
         return len(objects)
 
@@ -490,6 +490,6 @@ def _bulk_upsert_monthly(self, aggregations: dict) -> int:
                 "project",
                 "tag",
             ],
-            update_fields=["metric_type", "metric_value", "metric_count", "modified_at"],
+            update_fields=["metric_type", "metric_value", "metric_count"],
         )
         return len(objects)
diff --git a/backend/dashboard_metrics/models.py b/backend/dashboard_metrics/models.py
index 44fec5439a..2bc4baf6ac 100644
--- a/backend/dashboard_metrics/models.py
+++ b/backend/dashboard_metrics/models.py
@@ -3,7 +3,7 @@
 import uuid
 
 from django.db import models
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.models.organization_mixin import (
     DefaultOrganizationManagerMixin,
     DefaultOrganizationMixin,
@@ -25,19 +25,19 @@ class MetricType(models.TextChoices):
     HISTOGRAM = "histogram", "Histogram"
 
 
-class EventMetricsHourlyManager(DefaultOrganizationManagerMixin):
+class EventMetricsHourlyManager(DefaultOrganizationManagerMixin, BaseModelManager):
     """Manager for EventMetricsHourly with organization filtering."""
 
     pass
 
 
-class EventMetricsDailyManager(DefaultOrganizationManagerMixin):
+class EventMetricsDailyManager(DefaultOrganizationManagerMixin, BaseModelManager):
     """Manager for EventMetricsDaily with organization filtering."""
 
     pass
 
 
-class EventMetricsMonthlyManager(DefaultOrganizationManagerMixin):
+class EventMetricsMonthlyManager(DefaultOrganizationManagerMixin, BaseModelManager):
     """Manager for EventMetricsMonthly with organization filtering."""
 
     pass
diff --git a/backend/dashboard_metrics/tasks.py b/backend/dashboard_metrics/tasks.py
index 3246e7e46e..181c985137 100644
--- a/backend/dashboard_metrics/tasks.py
+++ b/backend/dashboard_metrics/tasks.py
@@ -121,7 +121,7 @@ def _bulk_upsert_hourly(aggregations: dict) -> int:
         objects,
         update_conflicts=True,
         unique_fields=["organization", "timestamp", "metric_name", "project", "tag"],
-        update_fields=["metric_type", "metric_value", "metric_count", "modified_at"],
+        update_fields=["metric_type", "metric_value", "metric_count"],
     )
     return len(objects)
 
@@ -160,7 +160,7 @@ def _bulk_upsert_daily(aggregations: dict) -> int:
         objects,
         update_conflicts=True,
         unique_fields=["organization", "date", "metric_name", "project", "tag"],
-        update_fields=["metric_type", "metric_value", "metric_count", "modified_at"],
+        update_fields=["metric_type", "metric_value", "metric_count"],
     )
     return len(objects)
 
@@ -199,7 +199,7 @@ def _bulk_upsert_monthly(aggregations: dict) -> int:
         objects,
         update_conflicts=True,
         unique_fields=["organization", "month", "metric_name", "project", "tag"],
-        update_fields=["metric_type", "metric_value", "metric_count", "modified_at"],
+        update_fields=["metric_type", "metric_value", "metric_count"],
     )
     return len(objects)
 
diff --git a/backend/pipeline_v2/models.py b/backend/pipeline_v2/models.py
index 00b12c8483..65fb5257a8 100644
--- a/backend/pipeline_v2/models.py
+++ b/backend/pipeline_v2/models.py
@@ -4,7 +4,7 @@
 from django.conf import settings
 from django.db import models
 from django.db.models import Q
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.models.organization_mixin import (
     DefaultOrganizationManagerMixin,
     DefaultOrganizationMixin,
@@ -18,7 +18,7 @@
 PIPELINE_NAME_LENGTH = 32
 
 
-class PipelineModelManager(DefaultOrganizationManagerMixin, models.Manager):
+class PipelineModelManager(DefaultOrganizationManagerMixin, BaseModelManager):
     def for_user(self, user):
         """Filter pipelines that the user can access:
         - Pipelines created by the user
diff --git a/backend/prompt_studio/prompt_studio_core_v2/models.py b/backend/prompt_studio/prompt_studio_core_v2/models.py
index 406c157efc..1e1802b776 100644
--- a/backend/prompt_studio/prompt_studio_core_v2/models.py
+++ b/backend/prompt_studio/prompt_studio_core_v2/models.py
@@ -8,7 +8,7 @@
 from django.db.models import QuerySet
 from utils.file_storage.constants import FileStorageKeys
 from utils.file_storage.helpers.prompt_studio_file_helper import PromptStudioFileHelper
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.models.organization_mixin import (
     DefaultOrganizationManagerMixin,
     DefaultOrganizationMixin,
@@ -21,7 +21,7 @@
 logger = logging.getLogger(__name__)
 
 
-class CustomToolModelManager(DefaultOrganizationManagerMixin, models.Manager):
+class CustomToolModelManager(DefaultOrganizationManagerMixin, BaseModelManager):
     def for_user(self, user: User) -> QuerySet[Any]:
         if getattr(user, "is_service_account", False):
             return self.all()
diff --git a/backend/prompt_studio/prompt_studio_registry_v2/models.py b/backend/prompt_studio/prompt_studio_registry_v2/models.py
index c4cd54cc0f..34478c8e70 100644
--- a/backend/prompt_studio/prompt_studio_registry_v2/models.py
+++ b/backend/prompt_studio/prompt_studio_registry_v2/models.py
@@ -5,7 +5,7 @@
 from account_v2.models import User
 from django.db import models
 from django.db.models import QuerySet
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.models.organization_mixin import (
     DefaultOrganizationManagerMixin,
     DefaultOrganizationMixin,
@@ -21,7 +21,7 @@
 logger = logging.getLogger(__name__)
 
 
-class PromptStudioRegistryModelManager(DefaultOrganizationManagerMixin, models.Manager):
+class PromptStudioRegistryModelManager(DefaultOrganizationManagerMixin, BaseModelManager):
     def get_queryset(self) -> QuerySet[Any]:
         return super().get_queryset()
 
diff --git a/backend/tags/models.py b/backend/tags/models.py
index 94c5c8cf54..7f366152b0 100644
--- a/backend/tags/models.py
+++ b/backend/tags/models.py
@@ -1,7 +1,7 @@
 import uuid
 
 from django.db import models
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.models.organization_mixin import (
     DefaultOrganizationManagerMixin,
     DefaultOrganizationMixin,
@@ -9,7 +9,7 @@
 from utils.user_context import UserContext
 
 
-class TagModelManager(DefaultOrganizationManagerMixin, models.Manager):
+class TagModelManager(DefaultOrganizationManagerMixin, BaseModelManager):
     def get_or_create_tags(self, tag_names: list[str]) -> list["Tag"]:
         """Retrieves or creates tags based on a list of tag names.
 
diff --git a/backend/tool_instance_v2/models.py b/backend/tool_instance_v2/models.py
index 971f1249bf..d858da2323 100644
--- a/backend/tool_instance_v2/models.py
+++ b/backend/tool_instance_v2/models.py
@@ -3,7 +3,7 @@
 from account_v2.models import User
 from django.db import models
 from django.db.models import QuerySet
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from workflow_manager.workflow_v2.models.workflow import Workflow
 
 TOOL_ID_LENGTH = 64
@@ -11,7 +11,7 @@
 TOOL_STATUS_LENGTH = 32
 
 
-class ToolInstanceManager(models.Manager):
+class ToolInstanceManager(BaseModelManager):
     def get_instances_for_workflow(self, workflow: uuid.UUID) -> QuerySet["ToolInstance"]:
         return self.filter(workflow=workflow)
 
diff --git a/backend/usage_v2/models.py b/backend/usage_v2/models.py
index 8da3d751ba..57ae3d143d 100644
--- a/backend/usage_v2/models.py
+++ b/backend/usage_v2/models.py
@@ -1,7 +1,7 @@
 import uuid
 
 from django.db import models
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.models.organization_mixin import (
     DefaultOrganizationManagerMixin,
     DefaultOrganizationMixin,
@@ -19,7 +19,7 @@ class LLMUsageReason(models.TextChoices):
     SUMMARIZE = "summarize", "Summarize"
 
 
-class UsageModelManager(DefaultOrganizationManagerMixin, models.Manager):
+class UsageModelManager(DefaultOrganizationManagerMixin, BaseModelManager):
     pass
 
 
diff --git a/backend/utils/models/base_model.py b/backend/utils/models/base_model.py
index b26f0f67d2..c2b288b9ef 100644
--- a/backend/utils/models/base_model.py
+++ b/backend/utils/models/base_model.py
@@ -1,9 +1,122 @@
 from django.db import models
+from django.utils import timezone
+
+_AUTO_NOW_FIELD = "modified_at"
+
+
+def _with_modified_at(fields):
+    """Return a new list containing ``fields`` plus ``modified_at`` if absent.
+
+    Centralises the "inject modified_at into a partial field list" rule so
+    ``bulk_update``, ``bulk_create`` and ``BaseModel.save`` apply it the same
+    way.
+    """
+    fields = list(fields)
+    if _AUTO_NOW_FIELD not in fields:
+        fields.append(_AUTO_NOW_FIELD)
+    return fields
+
+
+class BaseModelQuerySet(models.QuerySet):
+    """QuerySet that mirrors ``auto_now`` semantics for bulk update paths.
+
+    ``modified_at = models.DateTimeField(auto_now=True)`` only fires on
+    ``Model.save()``. ``QuerySet.update()`` and ``QuerySet.bulk_update()``
+    issue raw SQL and bypass ``save()``, leaving ``modified_at`` at whatever
+    value it had before the bulk path ran (creation time for never-saved
+    rows, the previous save() timestamp for others) — silently drifting the
+    audit trail. This QuerySet patches both paths so callers don't have to
+    remember.
+
+    Callers can still override by passing ``modified_at`` explicitly (or by
+    including ``modified_at`` in the ``fields`` list for ``bulk_update``).
+
+    Note: this is a manager-level convention, not a model-level guarantee.
+    Subclasses that reassign ``objects`` to a plain ``models.Manager``, raw
+    SQL, and migration-time models returned by ``apps.get_model()`` all
+    bypass these overrides.
+    """
+
+    def update(self, **kwargs):
+        kwargs.setdefault(_AUTO_NOW_FIELD, timezone.now())
+        return super().update(**kwargs)
+
+    def bulk_update(self, objs, fields, *args, **kwargs):
+        # Stamp modified_at on each obj only when the caller didn't list it;
+        # materialize objs first because we iterate the sequence twice (once
+        # to stamp, once via super()) and a generator would be exhausted.
+        if _AUTO_NOW_FIELD not in fields:
+            objs = list(objs)
+            now = timezone.now()
+            for obj in objs:
+                obj.modified_at = now
+            fields = _with_modified_at(fields)
+        return super().bulk_update(objs, fields, *args, **kwargs)
+
+    def bulk_create(
+        self, objs, *args, update_conflicts=False, update_fields=None, **kwargs
+    ):
+        # On upsert-on-conflict Django runs an UPDATE with only the listed
+        # fields, which skips auto_now the same way save(update_fields=...)
+        # does. Insert-only bulk_create already handles auto_now itself.
+        if update_conflicts and update_fields:
+            update_fields = _with_modified_at(update_fields)
+        return super().bulk_create(
+            objs,
+            *args,
+            update_conflicts=update_conflicts,
+            update_fields=update_fields,
+            **kwargs,
+        )
+
+
+BaseModelManager = models.Manager.from_queryset(BaseModelQuerySet)
 
 
 class BaseModel(models.Model):
+    """Abstract base with managed ``created_at`` / ``modified_at`` timestamps.
+
+    Subclasses inherit ``BaseModelManager`` as the default manager, which
+    auto-bumps ``modified_at`` on ``QuerySet.update()``, ``bulk_update()``
+    and upsert-mode ``bulk_create()``. The ``save()`` override below does
+    the same for partial ``save(update_fields=[...])`` calls.
+
+    Subclasses that need a custom manager should compose ``BaseModelManager``
+    (e.g. ``class FooManager(MyMixin, BaseModelManager)``) — otherwise the
+    auto-bump on bulk paths is silently lost.
+    """
+
     created_at = models.DateTimeField(auto_now_add=True)
     modified_at = models.DateTimeField(auto_now=True)
 
+    objects = BaseModelManager()
+
     class Meta:
         abstract = True
+
+    def save(
+        self,
+        force_insert=False,
+        force_update=False,
+        using=None,
+        update_fields=None,
+        **kwargs,
+    ):
+        # Django's save(update_fields=...) only writes the listed columns.
+        # auto_now still updates modified_at on the in-memory instance, but
+        # the new value is never persisted unless modified_at is in
+        # update_fields. Auto-include it so partial saves don't silently drop
+        # the bump. Preserve Django's documented no-op semantics for
+        # update_fields=[] (signals-only save, no column writes).
+        #
+        # Signature mirrors Django's positional order so callers passing
+        # force_insert/force_update positionally still hit this override.
+        if update_fields:
+            update_fields = _with_modified_at(update_fields)
+        return super().save(
+            force_insert=force_insert,
+            force_update=force_update,
+            using=using,
+            update_fields=update_fields,
+            **kwargs,
+        )
diff --git a/backend/utils/models/org_aware_manager.py b/backend/utils/models/org_aware_manager.py
index 3ec6e70bd7..ab40303dbb 100644
--- a/backend/utils/models/org_aware_manager.py
+++ b/backend/utils/models/org_aware_manager.py
@@ -3,15 +3,15 @@
 import logging
 
 from django.core.exceptions import ImproperlyConfigured
-from django.db import models
 from django.db.utils import OperationalError, ProgrammingError
+from utils.models.base_model import BaseModelManager
 from utils.models.org_path_discovery import get_org_path
 from utils.user_context import UserContext
 
 logger = logging.getLogger(__name__)
 
 
-class OrgAwareManager(models.Manager):
+class OrgAwareManager(BaseModelManager):
     """Manager that auto-discovers FK path to Organization and applies
     org filtering to all queries in request context.
 
diff --git a/backend/workflow_manager/endpoint_v2/models.py b/backend/workflow_manager/endpoint_v2/models.py
index e07737ba7a..44742dfc36 100644
--- a/backend/workflow_manager/endpoint_v2/models.py
+++ b/backend/workflow_manager/endpoint_v2/models.py
@@ -2,12 +2,12 @@
 
 from connector_v2.models import ConnectorInstance
 from django.db import models
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.user_context import UserContext
 from workflow_manager.workflow_v2.models.workflow import Workflow
 
 
-class WorkflowEndpointModelManager(models.Manager):
+class WorkflowEndpointModelManager(BaseModelManager):
     def get_queryset(self):
         # Validating organization
         organization = UserContext.get_organization()
diff --git a/backend/workflow_manager/file_execution/models.py b/backend/workflow_manager/file_execution/models.py
index d5106855e0..105b3875a9 100644
--- a/backend/workflow_manager/file_execution/models.py
+++ b/backend/workflow_manager/file_execution/models.py
@@ -4,7 +4,7 @@
 
 from django.db import models
 from utils.common_utils import CommonUtils
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 
 from workflow_manager.endpoint_v2.dto import FileHash
 from workflow_manager.workflow_v2.enums import ExecutionStatus
@@ -15,7 +15,7 @@
 MIME_TYPE_LENGTH = 128
 
 
-class WorkflowFileExecutionManager(models.Manager):
+class WorkflowFileExecutionManager(BaseModelManager):
     def get_or_create_file_execution(
         self,
         workflow_execution: Any,
diff --git a/backend/workflow_manager/internal_views.py b/backend/workflow_manager/internal_views.py
index d11ae56179..c822e5e7b5 100644
--- a/backend/workflow_manager/internal_views.py
+++ b/backend/workflow_manager/internal_views.py
@@ -7,7 +7,6 @@
 
 from django.db import transaction
 from django.shortcuts import get_object_or_404
-from django.utils import timezone
 from rest_framework import status, viewsets
 from rest_framework.decorators import action
 from rest_framework.response import Response
@@ -2009,7 +2008,6 @@ def post(self, request):
                         if update.get("execution_time") is not None:
                             execution.execution_time = update["execution_time"]
 
-                        execution.modified_at = timezone.now()
                         execution.save()
 
                         successful_updates.append(
diff --git a/backend/workflow_manager/workflow_v2/file_history_helper.py b/backend/workflow_manager/workflow_v2/file_history_helper.py
index 12b0a9c2c0..687f88dfe9 100644
--- a/backend/workflow_manager/workflow_v2/file_history_helper.py
+++ b/backend/workflow_manager/workflow_v2/file_history_helper.py
@@ -288,7 +288,6 @@ def _increment_file_history(
             result=str(result),
             metadata=FileHistoryHelper._safe_str(metadata),
             error=FileHistoryHelper._safe_str(error),
-            modified_at=timezone.now(),
         )
         # Refresh from DB to get updated values
         file_history.refresh_from_db()
diff --git a/backend/workflow_manager/workflow_v2/models/execution.py b/backend/workflow_manager/workflow_v2/models/execution.py
index 93623118d7..45886bd64e 100644
--- a/backend/workflow_manager/workflow_v2/models/execution.py
+++ b/backend/workflow_manager/workflow_v2/models/execution.py
@@ -12,7 +12,7 @@
 from usage_v2.helper import UsageHelper
 from usage_v2.models import Usage
 from utils.common_utils import CommonUtils
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 
 from workflow_manager.execution.dto import ExecutionCache
 from workflow_manager.execution.execution_cache_utils import ExecutionCacheUtils
@@ -26,7 +26,7 @@
 EXECUTION_ERROR_LENGTH = 256
 
 
-class WorkflowExecutionManager(models.Manager):
+class WorkflowExecutionManager(BaseModelManager):
     """Custom manager for WorkflowExecution model to handle user-specific filtering."""
 
     def for_user(self, user) -> QuerySet:
diff --git a/backend/workflow_manager/workflow_v2/models/workflow.py b/backend/workflow_manager/workflow_v2/models/workflow.py
index dd945fc7f9..0029f95997 100644
--- a/backend/workflow_manager/workflow_v2/models/workflow.py
+++ b/backend/workflow_manager/workflow_v2/models/workflow.py
@@ -4,7 +4,7 @@
 from django.conf import settings
 from django.core.validators import MinValueValidator
 from django.db import models
-from utils.models.base_model import BaseModel
+from utils.models.base_model import BaseModel, BaseModelManager
 from utils.models.organization_mixin import (
     DefaultOrganizationManagerMixin,
     DefaultOrganizationMixin,
@@ -15,7 +15,7 @@
 WORKFLOW_NAME_SIZE = 128
 
 
-class WorkflowModelManager(DefaultOrganizationManagerMixin, models.Manager):
+class WorkflowModelManager(DefaultOrganizationManagerMixin, BaseModelManager):
     def for_user(self, user):
         """Filter workflows that the user can access:
         - Workflows created by the user
diff --git a/backend/workflow_manager/workflow_v2/views.py b/backend/workflow_manager/workflow_v2/views.py
index dc428d948a..629b52bb22 100644
--- a/backend/workflow_manager/workflow_v2/views.py
+++ b/backend/workflow_manager/workflow_v2/views.py
@@ -6,7 +6,6 @@
 from django.db import transaction
 from django.db.models.query import QuerySet
 from django.shortcuts import get_object_or_404
-from django.utils import timezone
 from django.views.decorators.csrf import csrf_exempt
 from permissions.permission import IsOwner, IsOwnerOrSharedUserOrSharedToOrg
 from pipeline_v2.models import Pipeline
@@ -528,7 +527,6 @@ def status(self, request, id=None):
                 if validated_data.get("execution_time") is not None:
                     execution.execution_time = validated_data["execution_time"]
 
-                execution.modified_at = timezone.now()
                 execution.save()
 
                 logger.info(