Every month I do my agency's billing by hand: export timesheets from one system, create invoices in another, merge, email, file, upload to the accountant. I maintain ECA. Elsewhere, a multi-agency project runs from an Excel sheet nobody can keep current, because the spreadsheet is the only place people see everything and feel in control. Everybody orchestrates, most by hand, and not for lack of tools. ECA, Maestro, FlowDrop, Tool API, AI Integration - ECA 1.0.0 and the Orchestration module with Activepieces, soon n8n, could run my billing end to end today. But the builder opens five UIs and, worse, has to decide which engine runs which step. No user can make that decision. The fix is one UI: every component of every participating system on one canvas, engine routing done by the platform. The Modeler API, the Workflow Modeler, Tool API's typed contract and Post 6's shared vocabulary are that architecture. Missing: a composite model owner, a dispatcher, the cross-system data contract. Let's build them. In Drupal.