nacre: Skill for Claude Code

Changing the schema

Migrations live in packages/core/migrations, numbered and forward-only. Never edit a migration that has been applied anywhere; add another.

The schema is the source of truth for tenants, permissions, metadata, and audit. Vectors are in Qdrant, and originals in object storage where a deployment configured one (otherwise in documents.source_ref) — if a change would put content that needs a transaction into either of those, it belongs here instead.

Every table carrying tenant data

1. org_id NOT NULL REFERENCES organizations(id) ON DELETE CASCADE, even when it is reachable through a parent. The duplication is the point: it lets RLS work on the table directly.

2. Enable RLS, force it, and add the org_isolation policy in the same migration as the table:

   ALTER TABLE thing ENABLE ROW LEVEL SECURITY;
   ALTER TABLE thing FORCE  ROW LEVEL SECURITY;
   CREATE POLICY org_isolation ON thing
     USING (org_id = current_setting('app.current_org')::uuid);
   

   FORCE is not optional and its absence is silent. ENABLE alone does not apply to the role that owns the table, and migrations run as the owner — so any deployment that reuses that connection for the application gets policies that are switched on and inert. That was the state of this schema until migration 0002: a connection scoped to one organization could read another's documents, layers, and users, with every policy reporting enabled.

   Superusers bypass RLS regardless. The application must not connect as one, and withOrg's role option exists for deployments that cannot easily split the roles.

   RLS is the second line of defense, not the mechanism. The application still filters, and invariant 1 is still verified again at serialization. A table added without RLS is one forgotten WHERE away from a cross-tenant leak.

3. A foreign key that crosses tenants needs a composite key. A plain REFERENCES groups(id) lets a row join an object in one organization to an object in another. group_members had exactly that shape: one row joining a foreign user to a group would have handed that user every grant the group holds. Reference (id, org_id) against a UNIQUE (id, org_id) so the database enforces it rather than the code that writes the insert.

4. Indexes that the permission filter needs. A filter that falls back to a scan does not fail a test; it just gets slow enough to matter at a customer's volume, which is the worst way to find out.