claude-haiku-4.5 sub-agent fails with reasoning effort 'medium' not supported

Bug Report

Description

When the CLI internally routes sub-agent tasks to claude-haiku-4.5, it applies a medium reasoning effort, which is not supported by that model. This causes the following error:

Execution failed: Error: Reasoning effort 'medium' is not supported for model 'claude-haiku-4.5'

Steps to Reproduce

The error occurs during normal CLI usage when the task/explore sub-agent system selects claude-haiku-4.5 as the model with medium reasoning effort applied.

Expected Behavior

The CLI should not assign a reasoning effort level that is incompatible with the selected model. Either:

• Do not set reasoning effort for models that don't support it (e.g., claude-haiku-4.5)
• Map medium to a compatible default for claude-haiku-4.5
• Validate model/reasoning-effort compatibility before dispatch

Environment

• CLI Version: 1.0.79
• Model (main session): gpt-5.4
• Failing sub-agent model: claude-haiku-4.5
• OS: Linux

Comienza en la ruta de enrutamiento de sub-agents de task/explore y selección de modelos de la CLI descrita en el informe, donde claude-haiku-4.5 recibe el reasoning effort. Comprueba cómo se gestiona la compatibilidad entre el modelo y el effort; se considera terminado cuando el uso normal de la CLI ya no envía una configuración medium no compatible para ese modelo, con una comprobación de regresión si se encuentra la ubicación de prueba relevante.