[BUG] Cowork (Not Claude Code) 1M context window unavailable on Max 5x — regression from March 20

### Preflight Checklist - [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) 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? The 1M context window for Opus 4.6 is no longer available in Cowork, despite being available and working correctly as recently as March 21, 2026. Claude Code on the same account (Max 5x) still has full 1M context — this is a Cowork-only regression. ### What Should Happen? Cowork should use the 1M context window with Opus 4.6 on Max 5x, consistent with the March 13, 2026 GA announcement and consistent with Claude Code behavior on the same account. ### Error Messages/Logs ```shell None ``` ### Steps to Reproduce 1. Open Claude Desktop → Cowork mode 2. Start a new Cowork session with Opus 4.6 3. Check context window size (displayed next to model label. 4. Context shows "Opus 4.6" instead of "Opus 4.6 (1M Context)" 5. Start a new Code session, observe "Opus 4.6 (1M Context)" is showing. ### Claude Model Opus ### Is this a regression? Yes, this worked in a previous version ### Last Working Version _No response_ ### Claude Code Version Claude 1.1.7714 (3bd6f6) 2026-03-19T14:50:53.000Z ### Platform Anthropic API ### Operating System macOS ### Terminal/Shell Terminal.app (macOS) ### Additional Information _No response_

Posted by RevolutionaryTank on Mar 22, 2026, 11:55 AM

Tags

• github (SaaS)

Related issues

• 2026 - Microsoft Office 365
• [Ubuntu] `ubuntu-latest` label will use Ubuntu 26.04 in November 2026
• Gamut mapping
• [Codex Desktop] Editing and resending a queued message triggers "App-server queued follow-up no longer exists"
• [Windows] ChatGPT 26.820.60940 fails with "invalid transport in mcp_servers.codex_app"; Beta 26.727.40816 works
• [BUG]: infinite loading of videos