Optional reasoning effort for agents that support it. Codex maps this to model_reasoning_effort, Claude Code maps it to --effort, OpenCode maps it to --variant, and Antigravity CLI maps it to --effort. Common values include low, medium, high, xhigh, and max. Codex also supports ultra on compatible models, OpenCode supports minimal, and Antigravity CLI currently accepts low, medium, and high. You can instead append a recognized value to the model, such as gpt-5.6-sol:xhigh. This field takes precedence over that shorthand. Unsupported agents ignore this field.