> ## Documentation Index
> Fetch the complete documentation index at: https://braintrust.dev/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Gateway calls fail in bt eval --dev mode

export const plans_0 = "Any"

export const deployments_0 = "Any"

export const data_plane_version_0 = undefined

export const use_case_0 = "Use case - Running bt eval --dev and connecting to Playground when the task uses the Braintrust gateway and gateway calls fail with AI_APICallError: Not Found"

<Note>
  **Applies to:**

  * Plan - {plans_0}
  * Deployment - {deployments_0}
  * {data_plane_version_0}
  * {use_case_0}
</Note>

## Summary

**Issue:** Running `bt eval --dev <file>` and connecting to the Playground causes gateway calls to fail with `AI_APICallError: Not Found` when the AI SDK client reads `BRAINTRUST_API_KEY`.

**Cause:** `bt eval --dev` replaces `BRAINTRUST_API_KEY` with a short-lived Playground session token, which the Braintrust gateway does not accept as a valid credential.

**Resolution:** Pass your real API key to the gateway client via a separate environment variable that `bt eval --dev` does not overwrite.

## Environment variables injected by `bt eval --dev`

When the Playground connects to your local dev server, the following variables are overwritten in your process environment:

| Variable                     | Value injected                          |
| ---------------------------- | --------------------------------------- |
| `BRAINTRUST_API_KEY`         | Short-lived Playground session token    |
| `BRAINTRUST_API_URL`         | Your org's API URL                      |
| `BRAINTRUST_APP_URL`         | Dev server app URL                      |
| `BRAINTRUST_ORG_NAME`        | Org you connected from                  |
| `BRAINTRUST_DEFAULT_PROJECT` | Project from `--project` flag or config |

The session token injected into `BRAINTRUST_API_KEY` carries your identity but is not accepted by the Braintrust gateway (`gateway.braintrust.dev`). Only real API keys (`sk-...`) or service tokens (`bt-st-...`) authenticate successfully to the gateway.

## Resolution steps

### Step 1: Set a separate env var for your real API key

Before launching the dev server, set an additional variable in the same shell:

```bash theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
export BRAINTRUST_API_KEY_OVERRIDE=<your-real-api-key>
bt eval --dev <eval-file>
```

### Step 2: Update your gateway client to read the override first

```typescript theme={"theme":{"light":"github-light","dark":"github-dark-dimmed"}}
import { createOpenAI } from "@ai-sdk/openai";

const btGateway = createOpenAI({
  baseURL: process.env.OPENAI_BASE_URL ?? "https://gateway.braintrust.dev/v1",
  apiKey: process.env.BRAINTRUST_API_KEY_OVERRIDE ?? process.env.BRAINTRUST_API_KEY,
});
```

The fallback to `BRAINTRUST_API_KEY` ensures the client still works in non-dev contexts where the override is not set.

## Notes

* A `404 Not Found` from the AI SDK indicates a bad route or unaccepted credential at the gateway — not a missing org permission. A permission error would surface as `401` or `403`.
* Any env var name not in the injected list above can serve as the override. Common choices: `BRAINTRUST_API_KEY_OVERRIDE`, `BT_API_KEY`, `BT_GATEWAY_KEY`.
* This workaround is required any time your gateway client reads `BRAINTRUST_API_KEY` directly in dev mode.