[BUG] 1M context unavailable on Max plan — Windows 10

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?

• Claude Code version: v2.1.84
• Plan: Max (confirmed active at claude.ai/settings/billing) per screenshot - https://share.zight.com/BluwQQoA
• OS: Windows 10
• Model: Opus 4.6 (via Claude API)
• Auth: Claude Max subscription (no ANTHROPIC_API_KEY set)

What's Wrong?

Neither Sonnet or Opus 4.6 with 1M context is not available on a Max plan subscription. The /model picker shows only 3 model options with no 1M context variant. Manually requesting the 1M model returns an error.

Per the [1M context GA announcement (March 13, 2026)](https://claude.com/blog/1m-context-ga) and the [model configuration docs](https://code.claude.com/docs/en/model-config#extended-context-with-1m), 1M context should be automatically available on Max plans with no additional configuration.

> /model opus[1m]
  ⎿  Opus 4.6 with 1M context is not available for your account.
     Learn more: https://code.claude.com/docs/en/model-config#extended-context-with-1m

Context displays as X/200k rather than X/1000k.

Troubleshooting Already Attempted

• Confirmed no blocking environment variables are set:
• CLAUDE_CODE_DISABLE_1M_CONTEXT — not set
• No ANTHROPIC_DEFAULT_*_MODEL variables set
• No ANTHROPIC_API_KEY set (using native Max subscription auth)
• settings.json contains "model": "opus" — no pinned version ID
• claude logout + claude login — did not resolve
• Confirmed Max plan is active in billing settings

Environment Variable Check

PS> $env:CLAUDE_CODE_DISABLE_1M_CONTEXT
# (No output — not set)

PS> Get-ChildItem env: | Where-Object { $_.Name -like "*ANTHROPIC*DEFAULT*" }
# (No output — none set)

PS> Get-Content "$env:USERPROFILE\.claude\settings.json" | Select-String -Pattern "model"
# "model": "opus",

What Should Happen?

/model should show Opus 4.6 (1M context) as an option on Max plan. Running /model opus[1m] should activate the 1M context window.

Error Messages/Logs

Steps to Reproduce

1. Open Claude Code on Powershell with an active Max plan subscription
2. Run /model — no 1M context options are listed as per this screenshot https://share.zight.com/v1u74NYN
3. Run /model opus[1m] — returns error per this screenshot https://share.zight.com/d5uqPwRo
4. Run /context — shows X/200k instead of X/1000k per this screenshot https://share.zight.com/eDuOw8gE

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Not sure

Claude Code Version

2.1.84

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_