[BUG] Scheduled Tasks: Model selection in task setup UI not honored — tasks run on default model (Sonnet) regardless of configured model

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When a scheduled task is configured with a specific model (e.g., Opus 4.7) via the Claude Code Desktop App task setup UI, the task runs on a different model (claude-sonnet-4-6) at execution time. The model selection is not persisted.

To reproduce:

Create a scheduled task via the Desktop App
In task setup UI, select Opus 4.7 as the model
Allow the task to fire on its cron schedule
Observe that the task executes as claude-sonnet-4-6 (visible via system prompt: "You are powered by the model named Sonnet 4.6")
Evidence:

Both ~/.claude/settings.json and the project-level .claude/settings.json contain "model": "opus[1m]" — yet the scheduled session spawns as Sonnet
list_scheduled_tasks MCP output contains no model field per task, confirming the selection is not being stored
update_scheduled_task MCP schema has no model parameter — no API path to set model per task

Environment: Claude Code Desktop App, Windows 11, scheduled-tasks MCP

What Should Happen?

Expected: Task executes on the model selected at setup time.
Actual: Task executes on claude-sonnet-4-6 regardless of selection.

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce:

1. Open Claude Code Desktop App
2. Navigate to the Scheduled Tasks panel
3. Create a new scheduled task (or open an existing one)
4. In the task setup UI, select Opus 4.7 (or any non-default model) from the model dropdown
5. Save the task
6. Allow the task to fire on its cron schedule (or wait for the next scheduled run)
7. Observe the session header in the task's execution transcript

Expected: Task runs on the model selected in step 4 (claude-opus-4-7)
Actual: Task runs on claude-sonnet-4-6

Confirming evidence (no special setup needed):

Call the list_scheduled_tasks MCP tool — the response contains no model field for any task, confirming the selection is never stored
Check the update_scheduled_task MCP schema — it has no model parameter, so there is no API path to persist the selection

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Code 2.1.112

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_