diff --git a/src/tools/diagnostics.ts b/src/tools/diagnostics.ts
index b519424..c916d20 100644
--- a/src/tools/diagnostics.ts
+++ b/src/tools/diagnostics.ts
@@ -56,7 +56,7 @@ export const diagnosticsTools: PaperclipTool[] = [
   {
     name: 'diag_agents_missing_permissions',
     description:
-      'Agentes sem dangerouslySkipPermissions=true em adapter_config (check 11 health).',
+      'Agentes sem dangerouslySkipPermissions=true em adapter_config (NOTA: NÃO é RBAC — é flag Claude Code/CLI para correr sem prompts. Aplicar conscientemente por agent, não em massa).',
     inputSchema: { type: 'object', properties: {} },
     handler: async () => {
       const rows = await query(
@@ -441,4 +441,85 @@ export const diagnosticsTools: PaperclipTool[] = [
       return ok({ updated: rows.length, rows });
     },
   },
+
+  // 17 — WRITE
+  {
+    name: 'ensure_agent_membership',
+    description:
+      'WRITE: garante membership active em company_memberships para um agent (idempotente). Fix achado #2 sessão 5.',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        agent_id: { type: 'string', description: 'UUID do agente' },
+        membership_role: { type: 'string', description: 'Default "member"' },
+      },
+      required: ['agent_id'],
+    },
+    handler: async (args) => {
+      const agentId = String(args.agent_id ?? '');
+      const role = String(args.membership_role ?? 'member');
+      if (!agentId) throw new Error('agent_id obrigatório');
+      const existing = await query(
+        `SELECT id, status, membership_role FROM company_memberships
+         WHERE company_id = $1 AND principal_type = 'agent' AND principal_id = $2`,
+        [COMPANY_ID, agentId]
+      );
+      if (existing.length > 0) {
+        const rows = await query(
+          `UPDATE company_memberships
+           SET status = 'active', membership_role = $1, updated_at = NOW()
+           WHERE id = $2
+           RETURNING id, status, membership_role`,
+          [role, existing[0].id]
+        );
+        return ok({ action: 'updated', row: rows[0] });
+      }
+      const rows = await query(
+        `INSERT INTO company_memberships
+           (company_id, principal_type, principal_id, status, membership_role)
+         VALUES ($1, 'agent', $2, 'active', $3)
+         RETURNING id, status, membership_role`,
+        [COMPANY_ID, agentId, role]
+      );
+      return ok({ action: 'inserted', row: rows[0] });
+    },
+  },
+
+  // 18 — WRITE
+  {
+    name: 'grant_agent_permission',
+    description:
+      'WRITE: insere row em principal_permission_grants para um agent (idempotente por permission_key). Baseline RBAC. Fix achado #4.',
+    inputSchema: {
+      type: 'object',
+      properties: {
+        agent_id: { type: 'string', description: 'UUID do agente' },
+        permission_key: { type: 'string', description: 'Ex: tasks:assign, agents:create, runs:read' },
+        scope: { type: 'string', description: 'Scope opcional (default null)' },
+      },
+      required: ['agent_id', 'permission_key'],
+    },
+    handler: async (args) => {
+      const agentId = String(args.agent_id ?? '');
+      const permissionKey = String(args.permission_key ?? '');
+      const scope = args.scope ? String(args.scope) : null;
+      if (!agentId || !permissionKey) throw new Error('agent_id e permission_key obrigatórios');
+      const existing = await query(
+        `SELECT id FROM principal_permission_grants
+         WHERE company_id = $1 AND principal_type = 'agent' AND principal_id = $2 AND permission_key = $3`,
+        [COMPANY_ID, agentId, permissionKey]
+      );
+      if (existing.length > 0) {
+        return ok({ action: 'noop', existing: existing[0] });
+      }
+      const rows = await query(
+        `INSERT INTO principal_permission_grants
+           (company_id, principal_type, principal_id, permission_key, scope, granted_by_user_id)
+         VALUES ($1, 'agent', $2, $3, $4, 'mcp-bootstrap')
+         RETURNING id, permission_key, scope`,
+        [COMPANY_ID, agentId, permissionKey, scope]
+      );
+      return ok({ action: 'inserted', row: rows[0] });
+    },
+  },
 ];