diff --git a/.claude/scheduled_tasks.lock b/.claude/scheduled_tasks.lock
deleted file mode 100644
index d036fc78..00000000
--- a/.claude/scheduled_tasks.lock
+++ /dev/null
@@ -1 +0,0 @@
-{"sessionId":"3055829f-1a89-4359-93cc-ce9cd60f8636","pid":7243,"procStart":"Mon Apr 27 14:20:44 2026","acquiredAt":1777746434478}
\ No newline at end of file
diff --git a/.gitignore b/.gitignore
index 6766f2d6..bfc94f42 100644
--- a/.gitignore
+++ b/.gitignore
@@ -136,3 +136,4 @@ pr-guardian-phase1.patch
 
 # Local utility scripts (contain secrets, keep out of repo)
 rotate-postgres-password.sh
+.claude/scheduled_tasks.lock
diff --git a/prisma/migrations/20260529000000_rls_phase1_department/migration.sql b/prisma/migrations/20260529000000_rls_phase1_department/migration.sql
new file mode 100644
index 00000000..4efc4889
--- /dev/null
+++ b/prisma/migrations/20260529000000_rls_phase1_department/migration.sql
@@ -0,0 +1,44 @@
+-- Phase 1 Migration #4: Department RLS (TENANT_DIRECT)
+-- Apply order: #4 of 14 — org-chart hierarchy table; has parentId self-ref (same org only)
+-- Runbook: docs/rls-phase-1-cutover-runbook.md §2.3
+-- Template: skills/rls-rollout/templates/tenant-direct.sql.template
+
+-- 1. Composite index for RLS performance
+CREATE INDEX IF NOT EXISTS "Department_organizationId_id_idx"
+  ON "Department" ("organizationId", "id");
+
+-- 2. Enable RLS
+ALTER TABLE "Department" ENABLE ROW LEVEL SECURITY;
+ALTER TABLE "Department" FORCE ROW LEVEL SECURITY;
+
+-- 3. Grants
+GRANT SELECT, INSERT, UPDATE, DELETE ON "Department" TO app_user;
+GRANT SELECT, INSERT, UPDATE, DELETE ON "Department" TO admin_user;
+
+-- 4. Policies (admin_user has BYPASSRLS — no policies needed for it)
+CREATE POLICY department_select ON "Department"
+  FOR SELECT TO app_user
+  USING ("organizationId" = current_setting('app.current_org_id', true));
+
+CREATE POLICY department_insert ON "Department"
+  FOR INSERT TO app_user
+  WITH CHECK ("organizationId" = current_setting('app.current_org_id', true));
+
+CREATE POLICY department_update ON "Department"
+  FOR UPDATE TO app_user
+  USING ("organizationId" = current_setting('app.current_org_id', true))
+  WITH CHECK ("organizationId" = current_setting('app.current_org_id', true));
+
+CREATE POLICY department_delete ON "Department"
+  FOR DELETE TO app_user
+  USING ("organizationId" = current_setting('app.current_org_id', true));
+
+-- =========================================================================
+-- Rollback (commented — uncomment to revert)
+-- =========================================================================
+-- DROP POLICY IF EXISTS department_select ON "Department";
+-- DROP POLICY IF EXISTS department_insert ON "Department";
+-- DROP POLICY IF EXISTS department_update ON "Department";
+-- DROP POLICY IF EXISTS department_delete ON "Department";
+-- ALTER TABLE "Department" DISABLE ROW LEVEL SECURITY;
+-- DROP INDEX IF EXISTS "Department_organizationId_id_idx";
diff --git a/src/app/api/agents/[agentId]/department/route.ts b/src/app/api/agents/[agentId]/department/route.ts
index ee02512a..bd9025df 100644
--- a/src/app/api/agents/[agentId]/department/route.ts
+++ b/src/app/api/agents/[agentId]/department/route.ts
@@ -4,6 +4,7 @@ import { requireAgentOwner, isAuthError } from "@/lib/api/auth-guard";
 import { parseBodyWithLimit } from "@/lib/api/body-limit";
 import { prisma } from "@/lib/prisma";
 import { logger } from "@/lib/logger";
+import { withAdminBypass } from "@/lib/api/tenant-context";
 
 interface RouteParams {
   params: Promise<{ agentId: string }>;
@@ -56,7 +57,9 @@ export async function POST(request: NextRequest, { params }: RouteParams): Promi
   const { departmentId } = parsed.data;
 
   try {
-    const dept = await prisma.department.findUnique({ where: { id: departmentId }, select: { id: true } });
+    const dept = await withAdminBypass((db) =>
+      db.department.findUnique({ where: { id: departmentId }, select: { id: true } })
+    );
     if (!dept) return NextResponse.json({ success: false, error: "Department not found" }, { status: 404 });
 
     const updated = await prisma.agent.update({
diff --git a/src/app/api/departments/[departmentId]/route.ts b/src/app/api/departments/[departmentId]/route.ts
index fd16ab47..175fbbcf 100644
--- a/src/app/api/departments/[departmentId]/route.ts
+++ b/src/app/api/departments/[departmentId]/route.ts
@@ -4,6 +4,8 @@ import { requireOrgMember, isAuthError } from "@/lib/api/auth-guard";
 import { parseBodyWithLimit } from "@/lib/api/body-limit";
 import { prisma } from "@/lib/prisma";
 import { logger } from "@/lib/logger";
+import { withOrgContext } from "@/lib/db/rls-middleware";
+import { withAdminBypass } from "@/lib/api/tenant-context";
 
 interface RouteParams {
   params: Promise<{ departmentId: string }>;
@@ -16,10 +18,12 @@ const UpdateDepartmentSchema = z.object({
 });
 
 async function loadDepartment(departmentId: string) {
-  return prisma.department.findUnique({
-    where: { id: departmentId },
-    select: { id: true, organizationId: true, name: true, description: true, parentId: true, createdAt: true, updatedAt: true },
-  });
+  return withAdminBypass((db) =>
+    db.department.findUnique({
+      where: { id: departmentId },
+      select: { id: true, organizationId: true, name: true, description: true, parentId: true, createdAt: true, updatedAt: true },
+    })
+  );
 }
 
 export async function GET(
@@ -35,13 +39,15 @@ export async function GET(
   if (isAuthError(authResult)) return authResult;
 
   try {
-    const full = await prisma.department.findUnique({
-      where: { id: departmentId },
-      include: {
-        children: { select: { id: true, name: true, description: true } },
-        agents: { select: { id: true, name: true, model: true } },
-      },
-    });
+    const full = await withOrgContext(prisma, dept.organizationId, (tx) =>
+      tx.department.findUnique({
+        where: { id: departmentId },
+        include: {
+          children: { select: { id: true, name: true, description: true } },
+          agents: { select: { id: true, name: true, model: true } },
+        },
+      })
+    );
 
     return NextResponse.json({ success: true, data: full });
   } catch (error) {
@@ -81,20 +87,24 @@ export async function PATCH(
       if (parentId === departmentId) {
         return NextResponse.json({ success: false, error: "Department cannot be its own parent" }, { status: 422 });
       }
-      const parent = await prisma.department.findUnique({ where: { id: parentId }, select: { organizationId: true } });
+      const parent = await withOrgContext(prisma, dept.organizationId, (tx) =>
+        tx.department.findUnique({ where: { id: parentId }, select: { organizationId: true } })
+      );
       if (!parent || parent.organizationId !== dept.organizationId) {
         return NextResponse.json({ success: false, error: "Parent department not found in this org" }, { status: 422 });
       }
     }
 
-    const updated = await prisma.department.update({
-      where: { id: departmentId },
-      data: {
-        ...(name !== undefined && { name }),
-        ...(description !== undefined && { description }),
-        ...(parentId !== undefined && { parentId }),
-      },
-    });
+    const updated = await withOrgContext(prisma, dept.organizationId, (tx) =>
+      tx.department.update({
+        where: { id: departmentId },
+        data: {
+          ...(name !== undefined && { name }),
+          ...(description !== undefined && { description }),
+          ...(parentId !== undefined && { parentId }),
+        },
+      })
+    );
 
     return NextResponse.json({ success: true, data: updated });
   } catch (error) {
@@ -124,7 +134,9 @@ export async function DELETE(
       );
     }
 
-    await prisma.department.delete({ where: { id: departmentId } });
+    await withOrgContext(prisma, dept.organizationId, (tx) =>
+      tx.department.delete({ where: { id: departmentId } })
+    );
 
     return NextResponse.json({ success: true, data: null });
   } catch (error) {
diff --git a/src/app/api/departments/route.ts b/src/app/api/departments/route.ts
index bf3f0529..f1d82939 100644
--- a/src/app/api/departments/route.ts
+++ b/src/app/api/departments/route.ts
@@ -4,6 +4,7 @@ import { requireOrgMember, isAuthError } from "@/lib/api/auth-guard";
 import { parseBodyWithLimit } from "@/lib/api/body-limit";
 import { prisma } from "@/lib/prisma";
 import { logger } from "@/lib/logger";
+import { withOrgContext } from "@/lib/db/rls-middleware";
 
 const CreateDepartmentSchema = z.object({
   organizationId: z.string().cuid(),
@@ -23,13 +24,15 @@ export async function GET(request: NextRequest): Promise<NextResponse> {
   if (isAuthError(authResult)) return authResult;
 
   try {
-    const departments = await prisma.department.findMany({
-      where: { organizationId: orgId },
-      orderBy: { createdAt: "asc" },
-      include: {
-        _count: { select: { agents: true, children: true } },
-      },
-    });
+    const departments = await withOrgContext(prisma, orgId, (tx) =>
+      tx.department.findMany({
+        where: { organizationId: orgId },
+        orderBy: { createdAt: "asc" },
+        include: {
+          _count: { select: { agents: true, children: true } },
+        },
+      })
+    );
 
     return NextResponse.json({ success: true, data: departments });
   } catch (error) {
@@ -58,15 +61,19 @@ export async function POST(request: NextRequest): Promise<NextResponse> {
 
   try {
     if (parentId) {
-      const parent = await prisma.department.findUnique({ where: { id: parentId }, select: { organizationId: true } });
+      const parent = await withOrgContext(prisma, organizationId, (tx) =>
+        tx.department.findUnique({ where: { id: parentId }, select: { organizationId: true } })
+      );
       if (!parent || parent.organizationId !== organizationId) {
         return NextResponse.json({ success: false, error: "Parent department not found in this org" }, { status: 422 });
       }
     }
 
-    const department = await prisma.department.create({
-      data: { name, description, organizationId, parentId: parentId ?? null },
-    });
+    const department = await withOrgContext(prisma, organizationId, (tx) =>
+      tx.department.create({
+        data: { name, description, organizationId, parentId: parentId ?? null },
+      })
+    );
 
     return NextResponse.json({ success: true, data: department }, { status: 201 });
   } catch (error) {