[BUG] Dispatch (Cowork beta) ignores selected standard model and calls 1M context model — "Usage credits required for 1M context"

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?

Platform: Windows 11, Claude desktop app (latest, auto-updated), Cowork → Dispatch beta, Max plan. No CLI installed.
Description: Every Dispatch task fails with API Error: Usage credits required for 1M context · turn on usage credits at claude.ai/settings/usage, or use --model to switch to standard context.
What I verified:

Model selector shows Opus 4.8 (standard) selected, not the 1M variant
~/.claude/settings.json does not exist
ANTHROPIC_MODEL env var is not set
Dispatch has no model selector, so there is no user-side workaround

Expected: Dispatch should use the selected standard model.
Likely related: #64544, #63896, #39889

What Should Happen?

Platform: Windows 11, Claude desktop app (latest, auto-updated), Cowork → Dispatch beta, Max plan. No CLI installed.
Description: Every Dispatch task fails with API Error: Usage credits required for 1M context · turn on usage credits at claude.ai/settings/usage, or use --model to switch to standard context.
What I verified:

Model selector shows Opus 4.8 (standard) selected, not the 1M variant
~/.claude/settings.json does not exist
ANTHROPIC_MODEL env var is not set
Dispatch has no model selector, so there is no user-side workaround

Expected: Dispatch should use the selected standard model.
Likely related: #64544, #63896, #39889

Error Messages/Logs

API Error: Usage credits required for 1M context · turn on usage credits at claude.ai/settings/usage, or use --model to switch to standard context

Steps to Reproduce

Platform: Windows 11, Claude desktop app (latest, auto-updated), Cowork → Dispatch beta, Max plan. No CLI installed.
Description: Every Dispatch task fails with API Error: Usage credits required for 1M context · turn on usage credits at claude.ai/settings/usage, or use --model to switch to standard context.
What I verified:

Model selector shows Opus 4.8 (standard) selected, not the 1M variant
~/.claude/settings.json does not exist
ANTHROPIC_MODEL env var is not set
Dispatch has no model selector, so there is no user-side workaround

Expected: Dispatch should use the selected standard model.
Likely related: #64544, #63896, #39889

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

latest version

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Platform: Windows 11, Claude desktop app (latest, auto-updated), Cowork → Dispatch beta, Max plan. No CLI installed.
Description: Every Dispatch task fails with API Error: Usage credits required for 1M context · turn on usage credits at claude.ai/settings/usage, or use --model to switch to standard context.
What I verified:

Model selector shows Opus 4.8 (standard) selected, not the 1M variant
~/.claude/settings.json does not exist
ANTHROPIC_MODEL env var is not set
Dispatch has no model selector, so there is no user-side workaround

Expected: Dispatch should use the selected standard model.
Likely related: #64544, #63896, #39889