TL;DR: [Anchor Browser official docs, Batch Browser Sessions]: send the key as the `anchor-api-key` header on every request, for example

## Fix
1. [Anchor Browser official docs, Batch Browser Sessions]: send the key as the.
   Expected: this specific failure stops.
2. `anchor-api-key`.
   Expected: this specific failure stops.
3. header on every request, for example.
   Expected: this specific failure stops.
4. `-H "anchor-api-key value $ANCHOR_API_KEY"`.
   Expected: this specific failure stops.

## Details
[Anchor Browser official docs, Batch Browser Sessions]: send the key as the `anchor-api-key` header on every request, for example `-H "anchor-api-key value $ANCHOR_API_KEY"` . Requests with `Authorization: Bearer` fail auth. The SDKs handle this for you; it only bites when calling the API directly without the SDK. `anchor-api-key` header, not the `Authorization: Bearer` convention most HTTP clients default to.

## When to use
You hit exactly this: Anchor Browser: API auth uses the anchor-api-key header, not Authorization Bearer in Anchor Browser.

## When not to use
A different error, or the same symptom in a different tool. This page only covers the failure above.

## Compatibility
Anchor Browser.

## Edge cases
- Source context: Official docs (Batch Browser Sessions): documents the auth header gotcha that trips agents calling Anchor Browser's REST API directly.
- The API expects the key in a custom.