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title: Fix AI provider auth format and endpoint path after data plane v2 description: Resolve AI provider authentication failures after upgrading to data plane v2 by correcting auth_format values and removing empty endpoint_path fields. boost: 0.5 category: config ‘og:image’: ‘https://www.braintrust.dev/og?template=docs&title=Fix%20AI%20provider%20auth%20format%20and%20endpoint%20path%20after%20data%20plane%20v2

Applies to:
  • Plan -
  • Deployment -

Summary

After upgrading to data plane v2, AI provider configurations can fail if auth_format or endpoint_path metadata no longer matches the upstream provider. Data plane v2 respects auth_format when forwarding provider credentials and treats serialized endpoint_path: "" values differently, so affected providers need to be recreated or updated.

Symptoms

Model calls through Braintrust fail after upgrading to data plane v2, even though the same provider credentials worked before the upgrade. This issue usually affects provider configurations that include one or both of these metadata fields:
  • auth_format set to a value other than bearer.
  • endpoint_path: "" in the advanced configuration JSON.

Cause

Before data plane v2, Braintrust ignored auth_format in some provider configurations and sent provider credentials using Bearer authentication. Data plane v2 respects auth_format, so a provider configured with auth_format: api_key sends the credential as an API key instead of a Bearer token. Some provider configurations saved before March 17, 2026 serialized endpoint_path: "" into the configuration metadata. Remove endpoint_path from the advanced configuration JSON, or recreate the provider, to prevent the empty value from affecting provider routing.

Resolution steps

Step 1: Check the provider auth_format

Open the affected provider configuration and check the advanced configuration JSON. Provider configurations are under Settings > AI providers. Open the affected provider and check the advanced configuration JSON. If auth_format is set to a value other than bearer and the upstream provider expects Bearer authentication, recreate the provider with the correct auth_format.
Recreating a provider deletes the existing configuration. Any active requests routed through this provider will fail until the new configuration is saved.

Step 2: Remove an empty endpoint_path

If the provider configuration includes endpoint_path: "", delete endpoint_path from the advanced configuration JSON and save the configuration. If you cannot remove the field from the existing configuration, recreate the provider instead.

Step 3: Test the provider

Run the same model call again through Braintrust. If the call still fails, confirm that the upstream provider expects the authentication format configured in Braintrust.