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

Inizia dal percorso della CLI per il routing dei sub-agent task/explore e la selezione del modello descritto nel report, dove claude-haiku-4.5 riceve il reasoning effort. Verifica come viene gestita la compatibilità tra modello ed effort; il lavoro è concluso quando l'uso normale della CLI non invia più un'impostazione medium non supportata per quel modello, con un controllo di regressione se viene trovata la posizione del test pertinente.