Preserve history with logical model and agent deletion

backend/alembic/versions/202607221500_add_agent_model_deleted_at.py

@@ -0,0 +1,51 @@
+"""Add logical deletion markers for Agent and LLM Model.
+
+Revision ID: add_agent_model_deleted_at
+Revises: add_experience_revision_drafts
+Create Date: 2026-07-22 15:00:00
+"""
+
+from __future__ import annotations
+
+from collections.abc import Sequence
+
+from alembic import op
+import sqlalchemy as sa
+
+
+revision: str = "add_agent_model_deleted_at"
+down_revision: str | None = "add_experience_revision_drafts"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    op.add_column(
+        "agents",
+        sa.Column("deleted_at", sa.DateTime(timezone=True), nullable=True),
+    )
+    op.add_column(
+        "llm_models",
+        sa.Column("deleted_at", sa.DateTime(timezone=True), nullable=True),
+    )
+    op.create_index(
+        "ix_agents_active_tenant_created_at",
+        "agents",
+        ["tenant_id", "created_at"],
+        unique=False,
+        postgresql_where=sa.text("deleted_at IS NULL"),
+    )
+    op.create_index(
+        "ix_llm_models_active_tenant_created_at",
+        "llm_models",
+        ["tenant_id", "created_at"],
+        unique=False,
+        postgresql_where=sa.text("deleted_at IS NULL"),
+    )
+
+
+def downgrade() -> None:
+    op.drop_index("ix_llm_models_active_tenant_created_at", table_name="llm_models")
+    op.drop_index("ix_agents_active_tenant_created_at", table_name="agents")
+    op.drop_column("llm_models", "deleted_at")
+    op.drop_column("agents", "deleted_at")

backend/app/api/admin.py

@@ -196,7 +196,11 @@ async def toggle_company(
     # When disabling: pause all running agents
     if not new_state:
         agents = await db.execute(
-            select(Agent).where(Agent.tenant_id == company_id, Agent.status == "running")
+            select(Agent).where(
+                Agent.tenant_id == company_id,
+                Agent.status == "running",
+                Agent.deleted_at.is_(None),
+            )
         )
         for agent in agents.scalars().all():
             agent.status = "paused"