Create user_agent_auth.md (#5299)

* Create user_agent_auth.md

Adding documentation for agent authentication on behalf of a user

* Update user_agent_auth.md

* Rename user_agent_auth.md to user-agent-auth.md

* break content out to separate guides

* add links/overview

* edits

* fix sentence

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* Fix: Change 'get_user_config' fn name to 'my_node'

* Fix: Add reference to custom auth in MCP docs example

---------

Co-authored-by: Lauren Hirata Singh <lauren@langchain.dev>
This commit is contained in:
Jake Broekhuizen
2025-07-02 22:05:07 +00:00
committed by GitHub
co-authored by Lauren Hirata Singh
parent 89451f4ea2
commit 22e09d2739
9 changed files with 361 additions and 226 deletions
+48
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@@ -143,6 +143,54 @@ The returned user information is available:
In many of our tutorials, we will just show the "authorization" parameter to be concise, but you can opt to accept more information as needed
to implement your custom authentication scheme.
### Agent authentication
Custom authentication permits delegated access. The values you return in `@auth.authenticate` are added to the run context, giving agents user-scoped credentials lets them access resources on the user’s behalf.
```mermaid
sequenceDiagram
%% Actors
participant ClientApp as Client
participant AuthProv as Auth Provider
participant LangGraph as LangGraph Backend
participant SecretStore as Secret Store
participant ExternalService as External Service
%% Platform login / AuthN
ClientApp ->> AuthProv: 1. Login (username / password)
AuthProv -->> ClientApp: 2. Return token
ClientApp ->> LangGraph: 3. Request with token
Note over LangGraph: 4. Validate token (@auth.authenticate)
LangGraph -->> AuthProv: 5. Fetch user info
AuthProv -->> LangGraph: 6. Confirm validity
%% Fetch user tokens from secret store
LangGraph ->> SecretStore: 6a. Fetch user tokens
SecretStore -->> LangGraph: 6b. Return tokens
Note over LangGraph: 7. Apply access control (@auth.on.*)
%% External Service round-trip
LangGraph ->> ExternalService: 8. Call external service (with header)
Note over ExternalService: 9. External service validates header and executes action
ExternalService -->> LangGraph: 10. Service response
%% Return to caller
LangGraph -->> ClientApp: 11. Return resources
```
After authentication, the platform creates a special configuration object that is passed to your graph and all nodes via the configurable context.
This object contains information about the current user, including any custom fields you return from your [`@auth.authenticate`](../cloud/reference/sdk/python_sdk_ref.md#langgraph_sdk.auth.Auth.authenticate) handler.
To enable an agent to act on behalf of the user, use [custom authentication middleware](../how-tos/auth/custom_auth.md). This will allow the agent to interact with external systems like MCP servers, external databases, and even other agents on behalf of the user.
For more information, see the [Use custom auth](../how-tos/auth/custom_auth.md#enable-agent-authentication) guide.
### Agent authentication with MCP
For information on how to authenticate an agent to an MCP server, see the [MCP conceptual guide](../concepts/mcp.md).
## Authorization
After authentication, LangGraph calls your [`@auth.on`](../cloud/reference/sdk/python_sdk_ref.md#langgraph_sdk.auth.Auth.on) handlers to control access to specific resources (e.g., threads, assistants, crons). These handlers can: