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

# Agents & Models

> The three selectable agent providers, their model catalogs, reasoning-effort options, and interaction modes.

The agent is the AI coding system that runs inside your [workspace](/concepts/workspaces). Aether supports three selectable **agent providers** — Codex, Claude Code, and OpenCode — each wrapping a real coding-agent CLI with its own curated model catalog and authentication. You choose the agent type, model, interaction mode, and reasoning effort per task — and as project or account defaults.

The platform defaults are agent type `codex`, interaction mode `default`, and the `gpt-6.1-sol` model.

## Agent Providers

### Codex (default)

OpenAI Codex. The default agent type. Authenticate with a ChatGPT subscription (device OAuth) or an API key.

| Model slug | Name |
| - | - |
| `gpt-6-astra` | GPT-6 Astra |
| `gpt-6.1-sol` (default) | GPT-6.1 Sol |
| `gpt-6-sol` | GPT-6 Sol |
| `gpt-6-luna` | GPT-6 Luna |
| `gpt-5.6-sol` | GPT-5.6 Sol |
| `gpt-5.6-terra` | GPT-5.6 Terra |
| `gpt-5.6-luna` | GPT-5.6 Luna |
| `gpt-5.5` | GPT-5.5 |
| `gpt-5.4` | GPT-5.4 |
| `gpt-5.4-mini` | GPT-5.4 Mini |
| `gpt-5.3-codex-spark` | GPT-5.3 Codex Spark |

### Claude Code

Anthropic Claude Code. Authenticate with a Claude setup token.

| Model slug | Name |
| - | - |
| `claude-opus-5` | Claude Opus 5 |
| `claude-opus-5-5` (default) | Claude Opus 5.5 |
| `claude-fable-5-1` | Claude Fable 5.1 |
| `claude-sonnet-5-5` | Claude Sonnet 5.5 |
| `claude-sonnet-5` | Claude Sonnet 5 |
| `claude-sonnet-4-6` | Claude Sonnet 4.6 |
| `claude-haiku-4-5` | Claude Haiku 4.5 |

### OpenCode

The OpenCode agent, with a curated catalog of around 30 models routed through OpenRouter, OpenCode Zen, and Anthropic — including Claude, GPT, Gemini, DeepSeek, Mimo, Kimi, Qwen, and GLM variants. The default model is `opencode-claude-sonnet-4-6`. Authenticate by uploading an `auth.json` file; runtime model availability depends on that file's provider entitlements.

### Cursor (legacy)

Cursor is retired from new task selection; existing Cursor tasks and connections keep working. The Cursor agent (the `cursor-agent` CLI). Authenticate with a Cursor OAuth subscription.

| Model slug | Name |
| - | - |
| `claude-sonnet` (default) | Claude Sonnet 4.6 |
| `auto` | Auto (Cursor's selection) |
| `claude-haiku` | Claude Haiku 4.5 |
| `gpt-5` | GPT-5.5 |
| `gemini-3-pro` | Gemini 3.1 Pro |
| `grok-4` | Grok 4.3 |

For the connect/authentication steps for each provider, see [connecting agent providers](/guides/connect-agent-providers).

## Reasoning Effort

Reasoning effort controls how much the model thinks before acting. The available options depend on the agent provider:

| Provider | Default | Options |
| - | - | - |
| Codex | `xhigh` | `low`, `medium`, `high`, `xhigh`, `max`, `ultra` (model-dependent) |
| Claude Code | `xhigh` | `low`, `medium`, `high`, `xhigh`, `max`, `ultrathink`, `ultracode` |
| OpenCode | `high` | `low`, `medium`, `high`, `max` |
| Cursor (legacy) | `none` | `none` |

For Codex, GPT-6 Sol supports `low`, `medium`, `high`, `xhigh`, `max`, and `ultra`; GPT-6.1 Sol and GPT-6 Luna support the same set up to `max`.

For Claude Code, the full option set above applies to Fable 5.1, Opus 5.5, Opus 5, Sonnet 5.5, and Sonnet 5; Sonnet 4.6 uses the adaptive set `low`, `medium`, `high`, `ultrathink`. Cursor does not expose reasoning effort — its thinking parameters are encoded into the model itself.

## Interaction Modes

A task runs in one of two interaction modes:

* **`default`** — the agent works the task end to end.
* **`plan`** — the agent drafts a plan and halts for your approval before making changes. You review the plan and approve or send feedback before the agent proceeds.

## Selecting Per Task

Pick the harness, model, mode, and effort when creating a task. The harness stays fixed for that task; you can change its model, mode, and effort:

```bash theme={"dark"}
aether task create --project <project-id> --prompt "..." \
  --agent-type claude-code \
  --model claude-opus-5 \
  --interaction-mode plan \
  --reasoning-effort high
```

```bash theme={"dark"}
aether task update <task-id> --model claude-sonnet-4-6
```

You can also set these as project or account defaults so new tasks inherit them. See the [tasks guide](/guides/tasks) and the [agents and models guide](/guides/agents-and-models).


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