[BUG] Opus 4.6 with 1M context is not available on Max 5x plan

[take-sustainableand]

Preflight Checklist

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

What's Wrong?

Environment

• Claude Code version: 2.1.76 (latest)
• OS: Windows 11 Home
• Plan: Claude Max 5x

Description

When running /model Opus[1M] in Claude Code, the following error is returned:

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

Expected Behavior

The 1M extended context for Opus 4.6 should be available on the Max 5x plan, as documented.

Steps to Reproduce

1. Subscribe to Claude Max 5x plan
2. Update Claude Code to the latest version (2.1.76)
3. Run /model Opus[1M]
4. Observe the error message

Additional Context

The default Opus 4.6 model works fine. Only the 1M context variant is unavailable.

What Should Happen?

/model Opus[1M] should successfully switch to Opus 4.6 with 1M extended context on the Max 5x plan.

Error Messages/Logs

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

Steps to Reproduce

1. Subscribe to Claude Max 5x plan
2. Install/update Claude Code to version 2.1.76 (latest)
3. Run /model Opus[1M] in Claude Code
4. Error message appears: "Opus 4.6 with 1M context is not available for your account."

Note: The default /model command works fine and Opus 4.6 (without 1M) is available.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

No response

Claude Code Version

2.1.76

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Cursor

Additional Information

No response

[github-actions]

Found 3 possible duplicate issues:

1. [Bug] Anthropic API Error: Long context beta unavailable for Max plan with Claude Opus 4.6 1M #23700
2. [BUG] Opus 4.6 with [1m] context window returns "long context beta not available" on Max subscription #23472
3. sonnet[1m] not available on Max subscription despite docs not restricting it #26557

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
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🤖 Generated with Claude Code

[lucasmen9527]

Found a workaround via #34435:

Set the environment variable:

ANTHROPIC_DEFAULT_OPUS_MODEL=claude-opus-4-6[1m]

Or add it to ~/.claude/settings.json:

{
  "env": {
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "claude-opus-4-6[1m]"
  }
}

Both approaches work. The original question remains — shouldn't this be the default for Max subscribers?

[take-sustainableand]

Thank you！

[a4xrbj1]

Same problem as the other:

(v2.1.80, macOS M2, Max 5x, iTerm2)