diff --git a/app/database/seed-marketing.ts b/app/database/seed-marketing.ts
index 8baeb8d2..3e4d0c28 100644
--- a/app/database/seed-marketing.ts
+++ b/app/database/seed-marketing.ts
@@ -21,6 +21,8 @@ import { seedDefaultTemplates } from '../features/events/server/seed-templates.s
 import { EntranceKind } from '../features/territories/model/entrance-kind.type'
 import { TerritoryAttributionKind } from '../features/territories/model/territory-attribution-kind.type'
 import { TerritoryKind } from '../features/territories/model/territory-kind.type'
+import { syncBuiltInRoleAssignments } from '../shared/domain/built-in-roles.server'
+import { seedBuiltInRoles } from '../shared/domain/setup.server'
 import { Permission } from '../shared/types/permission'
 import { PublisherType } from '../shared/types/publisher-type'
 import { stripDiacritics } from '../shared/utils/strip-diacritics'
@@ -625,6 +627,11 @@ async function main() {
 
   console.log(`  ✓ Congregation "${congregation.name}" (id=${congId})`)
 
+  // Ensure built-in identity roles (`member`, `publisher`, `brother`, …) exist
+  // for this congregation even when the marketing seed runs on a fresh DB
+  // without the regular seed having run first.
+  await seedBuiltInRoles(prisma, congId)
+
   // ── Event templates ───────────────────────────────────────────────────
   await seedDefaultTemplates(prisma, congId, 'fr')
 
@@ -676,6 +683,11 @@ async function main() {
       },
     })
 
+    // Populate MemberRoleAssignment rows from the member's flags. The regular
+    // aggregate does this via syncBuiltInRoleAssignments; the direct
+    // prisma.member.create above bypasses it, so call it explicitly here.
+    await syncBuiltInRoleAssignments(prisma, member.id, congId, null)
+
     const account = await prisma.userAccount.upsert({
       where: { email },
       update: {},
diff --git a/app/shared/domain/built-in-roles.server.test.ts b/app/shared/domain/built-in-roles.server.test.ts
index b87b540a..f9ef3c8c 100644
--- a/app/shared/domain/built-in-roles.server.test.ts
+++ b/app/shared/domain/built-in-roles.server.test.ts
@@ -214,6 +214,23 @@ describe('syncBuiltInRoleAssignments', () => {
     )
   })
 
+  it('scopes the built-in role lookup to the congregation', async () => {
+    // Guards against cross-tenant assignments when the caller bypasses RLS
+    // (e.g. seed scripts running as the DB owner).
+    const db = makeDb({
+      member: { ...BASE, isPublisher: true },
+      builtInRoles: [{ id: 14, key: 'member' }],
+      existingAssignments: [],
+    })
+
+    await syncBuiltInRoleAssignments(db as never, 42, 7, 99)
+
+    expect(db.role.findMany).toHaveBeenCalledWith({
+      where: { isBuiltIn: true, congregationId: 7 },
+      select: { id: true, key: true },
+    })
+  })
+
   it('removes stale assignments and audits the diff', async () => {
     const db = makeDb({
       // Sister publisher only (no elder, since female cannot be elder)
diff --git a/app/shared/domain/built-in-roles.server.ts b/app/shared/domain/built-in-roles.server.ts
index 62726cbf..9491d765 100644
--- a/app/shared/domain/built-in-roles.server.ts
+++ b/app/shared/domain/built-in-roles.server.ts
@@ -94,8 +94,12 @@ export async function syncBuiltInRoleAssignments(
   })
   if (!member) return
 
+  // Scope by congregationId explicitly. Under RLS-scoped callers this is a
+  // no-op (rows are already filtered), but callers that bypass RLS — e.g. the
+  // seed scripts running as the DB owner — would otherwise match every
+  // congregation's built-in roles and write cross-tenant assignments.
   const builtInRoles = await db.role.findMany({
-    where: { isBuiltIn: true },
+    where: { isBuiltIn: true, congregationId },
     select: { id: true, key: true },
   })
 
diff --git a/scripts/check-aggregate-boundaries.test.ts b/scripts/check-aggregate-boundaries.test.ts
index faa67250..aa8f68f7 100644
--- a/scripts/check-aggregate-boundaries.test.ts
+++ b/scripts/check-aggregate-boundaries.test.ts
@@ -42,6 +42,20 @@ describe('analyzeSource — rule 1: writes on aggregate models', () => {
     }
   })
 
+  it('flags prisma.member.create outside an aggregate/allowlist file', () => {
+    const source = 'const m = await prisma.member.create({ data: {} })'
+    const v = analyzeSource('app/features/publishers/server/thing.server.ts', source)
+    expect(v).toHaveLength(1)
+    expect(v[0].rule).toBe('write-outside-aggregate')
+  })
+
+  it('allows the write inside an app/database seed script', () => {
+    const source = 'const m = await prisma.member.create({ data: {} })'
+    for (const path of ['app/database/seed.ts', 'app/database/seed-marketing.ts']) {
+      expect(analyzeSource(path, source)).toHaveLength(0)
+    }
+  })
+
   it('does not flag writes on non-aggregate models', () => {
     const source = 'await db.role.update({ where, data })'
     const v = analyzeSource('app/features/settings/server/roles.server.ts', source)
diff --git a/scripts/check-aggregate-boundaries.ts b/scripts/check-aggregate-boundaries.ts
index fae31211..0d32ecdc 100644
--- a/scripts/check-aggregate-boundaries.ts
+++ b/scripts/check-aggregate-boundaries.ts
@@ -2,10 +2,11 @@
 // CQRS-lite boundary check. Enforces two rules from
 // docs/development/architecture-conventions.md#cqrs-lite:
 //
-//   1. Writes to aggregate-owned models (`db.member.*` / `db.attribution.*`
+//   1. Writes to aggregate-owned models (`db.member.*` / `prisma.member.*` /
+//      `db.attribution.*` / `prisma.attribution.*` with
 //      create/update/updateMany/delete/deleteMany/upsert) are allowed only
 //      inside *.aggregate.ts files or on the allowlist (import-*.server.ts
-//      orchestrators, tests).
+//      orchestrators, tests, and app/database/** seed scripts).
 //
 //   2. UI-shaped reads inside *.aggregate.ts files (`findMany`, `count`,
 //      `aggregate`) are forbidden, unless the enclosing function is prefixed
@@ -27,13 +28,17 @@ const AGGREGATE_MODELS = ['member', 'attribution'] as const
 const WRITE_METHODS = ['create', 'update', 'updateMany', 'delete', 'deleteMany', 'upsert'] as const
 const UI_READ_METHODS = ['findMany', 'count', 'aggregate'] as const
 
-const WRITE_RE = new RegExp(`\\bdb\\.(${AGGREGATE_MODELS.join('|')})\\.(${WRITE_METHODS.join('|')})\\b`)
+const WRITE_RE = new RegExp(`\\b(?:db|prisma)\\.(${AGGREGATE_MODELS.join('|')})\\.(${WRITE_METHODS.join('|')})\\b`)
 const READ_RE = new RegExp(`\\bdb\\.\\w+\\.(${UI_READ_METHODS.join('|')})\\b`)
 const FUNCTION_DECL_RE = /^\s*(?:export\s+)?(?:async\s+)?function\s+(\w+)/
 const ALLOW_COMMENT_RE = /\/\/\s*aggregate-boundaries-allow\b/
 const TEST_FILE_RE = /\.(?:test|integration\.test|spec)\.tsx?$/
 const TEST_INFRA_RE = /^app\/tests\//
 const IMPORT_ORCHESTRATOR_RE = /\/import-[a-z-]+\.server\.ts$/
+// Seed scripts run before any aggregate is wired (no CongregationInfo / services)
+// and legitimately write via the raw client. This exemption used to live only
+// in prose in docs/development/architecture-conventions.md — enforce it here.
+const DB_SEED_RE = /^app\/database\//
 const TS_EXTENSION_RE = /\.tsx?$/
 
 function isCommentLine(line: string): boolean {
@@ -61,7 +66,8 @@ export function analyzeSource(relPath: string, source: string): Violation[] {
     relPath.endsWith('.aggregate.ts') ||
     IMPORT_ORCHESTRATOR_RE.test(relPath) ||
     TEST_FILE_RE.test(relPath) ||
-    TEST_INFRA_RE.test(relPath)
+    TEST_INFRA_RE.test(relPath) ||
+    DB_SEED_RE.test(relPath)
   const isAggregate = relPath.endsWith('.aggregate.ts')
 
   let currentFunction = ''