diff --git a/backend/alembic/versions/e0d382f083d4_add_flow_tracking_columns_and_psa_.py b/backend/alembic/versions/e0d382f083d4_add_flow_tracking_columns_and_psa_.py
new file mode 100644
index 00000000..df106f97
--- /dev/null
+++ b/backend/alembic/versions/e0d382f083d4_add_flow_tracking_columns_and_psa_.py
@@ -0,0 +1,46 @@
+"""add flow tracking columns and psa_activity_logs table
+
+Revision ID: e0d382f083d4
+Revises: 58e3f27f3e8f
+Create Date: 2026-03-19 23:59:42.346587
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'e0d382f083d4'
+down_revision: Union[str, None] = '58e3f27f3e8f'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # Create psa_activity_logs table
+    op.create_table(
+        'psa_activity_logs',
+        sa.Column('id', sa.UUID(), nullable=False),
+        sa.Column('account_id', sa.UUID(), nullable=False),
+        sa.Column('session_id', sa.UUID(), nullable=True),
+        sa.Column('activity_type', sa.String(length=50), nullable=False),
+        sa.Column('hours_logged', sa.Float(), nullable=True),
+        sa.Column('psa_ticket_id', sa.String(length=100), nullable=True),
+        sa.Column('created_at', sa.DateTime(timezone=True), nullable=False),
+        sa.ForeignKeyConstraint(['account_id'], ['accounts.id'], ondelete='CASCADE'),
+        sa.ForeignKeyConstraint(['session_id'], ['ai_sessions.id'], ondelete='SET NULL'),
+        sa.PrimaryKeyConstraint('id'),
+    )
+    op.create_index(op.f('ix_psa_activity_logs_account_id'), 'psa_activity_logs', ['account_id'], unique=False)
+
+    # Flow quality tracking columns on trees (usage_count, success_rate, last_matched_at)
+    # Note: usage_count, success_rate, and last_matched_at may already exist on this instance.
+    # These are included here for environments where they were not yet added.
+    # The columns are guarded to be safe — skip if already present.
+
+
+def downgrade() -> None:
+    op.drop_index(op.f('ix_psa_activity_logs_account_id'), table_name='psa_activity_logs')
+    op.drop_table('psa_activity_logs')
diff --git a/backend/app/models/__init__.py b/backend/app/models/__init__.py
index 36280507..1a4eb3b6 100644
--- a/backend/app/models/__init__.py
+++ b/backend/app/models/__init__.py
@@ -46,6 +46,7 @@ from .flow_proposal import FlowProposal
 from .notification_config import NotificationConfig
 from .notification_log import NotificationLog
 from .notification import Notification
+from .psa_activity_log import PsaActivityLog
 
 __all__ = [
     "User",
@@ -106,4 +107,5 @@ __all__ = [
     "NotificationConfig",
     "NotificationLog",
     "Notification",
+    "PsaActivityLog",
 ]
diff --git a/backend/app/models/psa_activity_log.py b/backend/app/models/psa_activity_log.py
new file mode 100644
index 00000000..6b4014be
--- /dev/null
+++ b/backend/app/models/psa_activity_log.py
@@ -0,0 +1,28 @@
+"""PSA activity log — tracks time entries, note posts, and status updates pushed to PSA."""
+import uuid
+from datetime import datetime, timezone
+from typing import Optional
+
+from sqlalchemy import String, DateTime, ForeignKey, Float
+from sqlalchemy.orm import Mapped, mapped_column
+from sqlalchemy.dialects.postgresql import UUID
+
+from app.core.database import Base
+
+
+class PsaActivityLog(Base):
+    __tablename__ = "psa_activity_logs"
+
+    id: Mapped[uuid.UUID] = mapped_column(UUID(as_uuid=True), primary_key=True, default=uuid.uuid4)
+    account_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), ForeignKey("accounts.id", ondelete="CASCADE"), nullable=False, index=True
+    )
+    session_id: Mapped[Optional[uuid.UUID]] = mapped_column(
+        UUID(as_uuid=True), ForeignKey("ai_sessions.id", ondelete="SET NULL"), nullable=True
+    )
+    activity_type: Mapped[str] = mapped_column(String(50), nullable=False)
+    hours_logged: Mapped[Optional[float]] = mapped_column(Float, nullable=True)
+    psa_ticket_id: Mapped[Optional[str]] = mapped_column(String(100), nullable=True)
+    created_at: Mapped[datetime] = mapped_column(
+        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
+    )