diff --git a/docs/my-website/docs/proxy/config_settings.md b/docs/my-website/docs/proxy/config_settings.md
index 544ace9063a..89c1febe24a 100644
--- a/docs/my-website/docs/proxy/config_settings.md
+++ b/docs/my-website/docs/proxy/config_settings.md
@@ -285,6 +285,7 @@ router_settings:
 | always_include_stream_usage | boolean | If true, includes usage metrics in every streaming response chunk |
 | auto_redirect_ui_login_to_sso | boolean | If true, automatically redirects UI login page to SSO provider |
 | control_plane_url | string | URL of the control plane for cross-instance state sharing |
+| enable_post_custom_auth_checks | boolean | If true, runs LiteLLM post-custom-auth checks (for example expiry, end-user budget, and model budget checks) on `UserAPIKeyAuth` objects returned by custom auth handlers. Default is false for performance. |
 | custom_auth_run_common_checks | boolean | If true, runs standard auth validation checks alongside custom auth handlers |
 | custom_ui_sso_sign_in_handler | string | Custom handler for SSO sign-in logic in the UI |
 | database_connection_pool_timeout | integer | Database connection pool timeout in seconds |
diff --git a/docs/my-website/docs/proxy/custom_auth.md b/docs/my-website/docs/proxy/custom_auth.md
index 3d46e1074cc..4832af9eb32 100644
--- a/docs/my-website/docs/proxy/custom_auth.md
+++ b/docs/my-website/docs/proxy/custom_auth.md
@@ -230,6 +230,28 @@ general_settings:
 
 [**Implementation Code**](https://github.com/BerriAI/litellm/blob/caf2a6b279ddbe89ebd1d8f4499f65715d684851/litellm/proxy/utils.py#L122)
 
+### Optional: run LiteLLM's post-custom-auth checks
+
+If your custom auth function returns a `UserAPIKeyAuth` object and you want LiteLLM to run the built-in checks on that object, enable the following flags in `general_settings`:
+
+```yaml
+general_settings:
+  custom_auth: custom_auth.user_api_key_auth
+  enable_post_custom_auth_checks: true   # opt in to LiteLLM post-auth checks
+  custom_auth_run_common_checks: true    # optional: also run standard model access checks
+```
+
+What each flag does:
+
+- `enable_post_custom_auth_checks: true`
+  - Runs LiteLLM's post-custom-auth validation on the returned `UserAPIKeyAuth`
+  - This includes checks such as key expiry, end-user budget enforcement, and per-model budget enforcement
+- `custom_auth_run_common_checks: true`
+  - Runs the common model-access / fallback checks inside the post-custom-auth flow
+  - This flag only has an effect when `enable_post_custom_auth_checks` is also enabled
+
+By default, `enable_post_custom_auth_checks` is `false`. This keeps trusted custom-auth deployments on the fast path and avoids extra DB-backed checks unless you explicitly opt in.
+
 #### 3. Start the proxy
 ```shell
 $ litellm --config /path/to/config.yaml