---
question: How do I authorize calls to agent and workflow routes?
kind: guide
next:
  - /api/authentication
  - /v2/capabilities/build/agents/chat-with-an-agent
---

> **You are reading the v2.x docs (engine modules). New projects use v3.** [Read this page in v3](/capabilities/platform/authenticate-engine-api) · [Migrate from 2.x to 3.0](/capabilities/upgrade/migrate-to-3)

# 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](/v2/capabilities/get-started/sign-in) for `POST /api/auth/login`.