Make Your LangSmith Deployment Multi-Tenant

When you deploy an agent on LangSmith, you get a full agent server with 30+ API endpoints out of the box — threads, runs, assistants, a built-in store, A2A and MCP protocol support. But by default, everything is scoped to the API key. Any user can see every thread, every conversation.

In this video, I show you how to add custom authentication to your deployment so that every user gets their own scoped threads, runs, and conversation history — enforced by the deployment itself. We'll use Supabase for auth, but you can plug in any provider (Auth0, Clerk, etc.).

What we cover:
- Why multi-tenancy matters for deployed agents
- The auth.authenticate handler — validating tokens from your auth provider
- The auth.on handler — automatically scoping resources per user
- Permission-based access — restricting actions by role (e.g., only admins can create crons)
- A full live demo with two users on the same deployment

The entire auth layer is about 40 lines of Python — three decorators, no custom middleware.

Links:
- Repo: https://github.com/langchain-samples/lsd-custom-route-react-ui
- LangSmith Deployments docs: https://docs.langchain.com/langsmith/deployments
- Custom auth docs: https://docs.langchain.com/langsmith/auth
- Supabase: https://supabase.com

Chapters:
00:00 Intro
00:20 Agent Server with Basic Auth
02:38 Custom Authentication
03:28 Implementing Multi-Tenant Auth
09:48 Testing Locally  
10:41 Deploying on LangSmith Deployment
12:15 Multi-Tenant Demo