---
question: How do I authorize calls to agent and workflow routes?
kind: guide
next:
  - /api/authentication
  - /capabilities/build/agents/chat-with-an-agent
---

# Authenticate engine API requests

Routes on the ABI process (`/agents`, `/workflows`, `/pipelines`, `/tools`) check `ABI_API_KEY`. A Nexus login token does not satisfy them.

Send the key as `Authorization: Bearer $ABI_API_KEY`, or as the `token` query parameter on supported routes. The generated reference lists each operation; the shared rules are on [API authentication](/api/authentication).

From the CLI, `abi chat` and `abi agent list` use the running engine and pick up the same key from the environment. Nexus sign-in is separate: see [Sign in to Nexus](/capabilities/get-started/sign-in) for `POST /api/auth/login`.