---
question: How do I make an agent available for chat?
kind: task
via_web: available
via_cli: na
via_python: na
via_api: available
via_config: available
ref_web: Settings › Agents
ref_api: PATCH /api/agents/{id}
ref_config: agents:
next:
  - /v2/capabilities/build/agents/chat-with-an-agent
  - /v2/capabilities/build/agents/edit-prompt-and-model
---

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

# Enable in a workspace

Each Nexus workspace keeps its own record of every agent, with an on/off switch. The chat offers only the enabled ones. This is the business workspace (members, chat), not a code workspace.

Each time a workspace [syncs](#when-a-workspace-syncs), the engine's agents are switched from `config.yaml`: the workspace's `agents:` list when it has one, otherwise only the default agent. `naas_abi`'s Abi agent is added to every list. Every sync turns the default agent back on: to turn it off, change `default_agent` first.

What a switch set by hand, in Nexus or with the API, does at the next sync depends on the ABI line:

| ABI line | A switch set by hand |
|---|---|
| ABI 2.x | Lasts until the next sync, which sets every engine agent back to the list. To keep an agent on or off, change the `agents:` list. |
| ABI 3.x | Wins over the list from then on, except for the default agent. |

## Web UI

### Open the agent list

In the workspace, open Settings › Agents. The header shows how many agents are enabled.

### Switch the agent

Check or clear the **Enabled** box on the agent's row (its tooltip reads **Enable agent** or **Disable agent**). The change is saved at once.

**Edit Agent** has the same **Enabled** box, saved with **Save**. The **Status** filter shows only enabled or disabled agents.

![Workspace Settings on Agents, enabled agents](/abi/Screenshot_Agents.png)

*Settings › Agents, filtered to enabled agents. The Enabled box switches an agent on or off for this workspace.*

## CLI

Not applicable. No `abi` command switches an agent (`abi workspace` manages members, not agents): use the Web UI, the REST API or the `agents:` list.

## Python

Not applicable. Each workspace, not the agent class, decides where an agent is on: use the `agents:` list, the Web UI or the REST API.

## REST API

### Find the agent's id

```http
GET /api/agents/?workspace_id=<id>
```

It lists the workspace's agents with their `id` and `enabled`. `POST /api/agents/sync?workspace_id=<id>` first creates the records of agents loaded since the last sync.

### Switch it

```http
PATCH /api/agents/{id}
```

```json title="Request body"
{ "enabled": true }
```

Send `false` to turn it off. Auth: a Nexus session with access to the workspace.

## Config

### List the workspace's agents

Workspaces are declared in `naas_abi`'s `nexus_config`. Give one an `agents:` list, each entry `<module> <AgentClass>`, and optionally its own `default_agent`:

```yaml title="config.yaml"
modules:
  - module: naas_abi
    enabled: true
    config:
      nexus_config:
        organizations:
          - name: "Dev"
            slug: "dev"
            workspaces:
              - name: "Default"
                slug: "default"
                default_agent: "my_module ReviewerAgent"
                agents:
                  - "my_module ReviewerAgent"
                  - "naas_abi OntologyEngineerAgent"
```

### Restart and sync

Restart the engine. The workspace's next sync turns on the listed agents and turns off the others, except Abi (and, on ABI 3.x, the agents switched by hand). A workspace without `agents:` gets only its default agent: its own `default_agent`, or the project's top-level one. The default agent is always on.

## When a workspace syncs

A sync reconciles one workspace's agent records with the agents the engine loaded: it adds the new ones, deletes the records of classes that are gone, and applies the `agents:` list. It runs for that workspace only, when someone opens an agent's **Edit Agent** page, when someone opens the chat pane (once per page load), or on `POST /api/agents/sync?workspace_id=<id>`. On ABI 3.x, opening the Settings › Agents list also syncs; on ABI 2.x it does not.