Credential Routing Models

• Agent-owned secrets centralize a single, shared key for all users, demonstrated using a Tavily API key for universal web search functions where individual identity is unnecessary.0:32
• User-owned OAuth via MCP allows agents to leverage existing Model Context Protocol tools, triggering an approval flow that ensures actions are performed under the end user's specific identity rather than a service account.2:48
• Custom OAuth apps provide a flexible, third mode for bespoke integrations, allowing developers to define custom tools that fetch, cache, or refresh user tokens dynamically via connections.get.5:26

Core Mechanism

• The connections.get function acts as the primary abstraction layer for developers, automatically determining whether to pass a cached valid token, trigger an OAuth approval flow, or perform a token refresh on demand.7:02
• While MCP connections offer a streamlined, automated discovery process for pre-built tools, custom OAuth integrations require specific manual registration of client IDs, secrets, and scope permissions within the LangSmith environment.
• Correct configuration of redirect URIs remains the most critical technical bottleneck for custom OAuth implementations, as misconfiguration prevents the successful completion of the user-authorization handshake.6:02