Models
Choose the model a session runs on.
Send exactly one claude_code, codex, or gemini block to choose Claude Code, Codex, or Gemini CLI, and set its model.
JSON
1
{
2
"claude_code": {
3
"model": "claude-opus-5-5",
4
"prompt": "Find and fix the failing test."
5
}
6
}
Current support
| Model | ID | Runs in |
|---|---|---|
| Claude Fable 5.1 | claude-fable-5-1 | Claude Code |
| Claude Opus 5.5 | claude-opus-5-5 | Claude Code |
| Claude Sonnet 5.5 | claude-sonnet-5-5 | Claude Code |
| Claude Haiku 5.5 | claude-haiku-5-5 | Claude Code |
| GPT-6.1 Sol | gpt-6.1-sol | Codex |
| GPT-6 Astra | gpt-6-astra | Codex |
| GPT-6 Sol | gpt-6-sol | Codex |
| GPT-6 Luna | gpt-6-luna | Codex |
| Gemini 4 Argon | gemini-4-argon | Gemini CLI |
| Gemini 3.8 Flash | gemini-3.8-flash | Gemini CLI |
Claude Code also accepts claude-fable, claude-opus, claude-sonnet, and claude-haiku for the newest model in each family. See Pricing for token prices.
GET /v1/account/models returns the same list with each model's features. A session that asks for a feature its model doesn't support fails with unsupported_session_combination before it starts.
Every session names its model. In the CLI, el model use claude-opus-5-5 sets the model a bare el "..." runs on when --model is absent.