diff --git a/backend/alembic/versions/7f4e2c1a9a10_ensure_human_employee_id_is_1.py b/backend/alembic/versions/7f4e2c1a9a10_ensure_human_employee_id_is_1.py
new file mode 100644
index 00000000..caf875af
--- /dev/null
+++ b/backend/alembic/versions/7f4e2c1a9a10_ensure_human_employee_id_is_1.py
@@ -0,0 +1,104 @@
+"""Ensure human employee id is 1
+
+Revision ID: 7f4e2c1a9a10
+Revises: 3f2c1b9c8e12
+Create Date: 2026-02-02
+
+"""
+
+from __future__ import annotations
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "7f4e2c1a9a10"
+down_revision = "3f2c1b9c8e12"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    """If the (single) human employee exists but is not id=1, move it to id=1.
+
+    This is a dev ergonomics migration: a bunch of code / examples assume the
+    primary human user is employee_id=1.
+
+    Safe behavior:
+    - Only runs when there is exactly one human employee.
+    - Only runs when employee id=1 is currently unused.
+    - Rewrites all known FKs that point at the old id.
+    """
+
+    conn = op.get_bind()
+
+    human_ids = [
+        row[0]
+        for row in conn.execute(sa.text("SELECT id FROM employees WHERE employee_type='human' ORDER BY id"))
+    ]
+
+    # Only attempt the rewrite in the "typical dev" scenario.
+    if len(human_ids) != 1:
+        return
+
+    old_id = int(human_ids[0])
+    if old_id == 1:
+        return
+
+    id1_exists = conn.execute(sa.text("SELECT 1 FROM employees WHERE id=1")).first() is not None
+    if id1_exists:
+        return
+
+    # Update foreign keys in known tables/columns.
+    conn.execute(
+        sa.text("UPDATE departments SET head_employee_id=1 WHERE head_employee_id=:old_id"),
+        {"old_id": old_id},
+    )
+    conn.execute(
+        sa.text("UPDATE teams SET lead_employee_id=1 WHERE lead_employee_id=:old_id"),
+        {"old_id": old_id},
+    )
+    conn.execute(
+        sa.text("UPDATE employees SET manager_id=1 WHERE manager_id=:old_id"),
+        {"old_id": old_id},
+    )
+    conn.execute(
+        sa.text("UPDATE activities SET actor_employee_id=1 WHERE actor_employee_id=:old_id"),
+        {"old_id": old_id},
+    )
+    conn.execute(
+        sa.text("UPDATE project_members SET employee_id=1 WHERE employee_id=:old_id"),
+        {"old_id": old_id},
+    )
+    conn.execute(
+        sa.text("UPDATE tasks SET assignee_employee_id=1 WHERE assignee_employee_id=:old_id"),
+        {"old_id": old_id},
+    )
+    conn.execute(
+        sa.text("UPDATE tasks SET reviewer_employee_id=1 WHERE reviewer_employee_id=:old_id"),
+        {"old_id": old_id},
+    )
+    conn.execute(
+        sa.text("UPDATE tasks SET created_by_employee_id=1 WHERE created_by_employee_id=:old_id"),
+        {"old_id": old_id},
+    )
+    conn.execute(
+        sa.text("UPDATE task_comments SET author_employee_id=1 WHERE author_employee_id=:old_id"),
+        {"old_id": old_id},
+    )
+
+    # Finally, rewrite the employee PK itself.
+    conn.execute(sa.text("UPDATE employees SET id=1 WHERE id=:old_id"), {"old_id": old_id})
+
+    # Keep the sequence in sync (Postgres).
+    conn.execute(
+        sa.text(
+            "SELECT setval(pg_get_serial_sequence('employees','id'), (SELECT COALESCE(MAX(id), 1) FROM employees), true)"
+        )
+    )
+
+
+def downgrade() -> None:
+    # Non-reversible in a safe way; this is a dev convenience migration.
+    pass