Claude Code
Models, options, and features for Claude Code.
Send a claude_code block to run a session with Claude Code:
JSON
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{
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"claude_code": {
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"prompt": "Find and fix the failing test.",
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"model": "claude-opus-5-5",
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"effort": "high"
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}
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}
In agent YAML, the same fields go under session.claude_code. The CLI picks the harness from --model.
Options
The task.
A Claude Code model from Models.
Reasoning effort, where the model supports it.
The most turns the agent can take on each message, a whole number above 0.
The model Claude Code switches to when model is overloaded. Default none.
A Claude Code settings.json in a repository, applied below the settings Ellipsis manages. Hooks stay disabled.
| Model | Effort levels | Default effort |
|---|---|---|
| Claude Opus 5.5, Sonnet 5.5, and Haiku 5.5 | All 5 | medium |
| Claude Fable 5.1 | All 5 | high |
Features
| Feature | Support |
|---|---|
| Follow-up messages | All models |
| MCP servers | All models |
| JSON output | All models |
| Skills | Not supported; use Codex |
| Images in messages | All models |
| Settings file | All models |