Hi @0pen7ech ,
Great question — and honestly, I think the answer is: all three, by design.
LangGraph Approval Hub gives teams freedom of choice depending on where they sit:
• UI dashboard — a non-technical reviewer (CFO, legal, ops) approves directly from the interface, no code needed
• Python SDK — a developer embeds approval gates inline inside their LangGraph agent, same runtime
• External policy gate — your exact use case: a cross-framework boundary that any agent (LangGraph, CrewAI, AutoGen, whatever) can call via the API, so the same approval logic and audit trail applies regardless of the underlying framework
The approval state lives in Supabase, so it’s decoupled from any single runtime — that’s what makes the third option possible.
One more thing: since the whole stack is open source (Next.js + Supabase), teams can customize the UI and backend to fit their exact workflow. And because the codebase is straightforward, you can use Claude to modify it — tweak the dashboard layout, adjust the policy schema, add new notification channels — without needing to deeply understand every file first.
Your MCP supervision boundary sounds like it maps cleanly onto that third path.