Opus 4.6 update implies 1M context but Claude Code hard-caps at 200K — causes session crashes (Max 20x)

[w0lf69]

Bug Description

After updating Claude Code to v2.1.34 (which includes Opus 4.6), the release notes and model description prominently advertise "1M token context window." However, Claude Code is hard-capped at 200K tokens because the 1M context is an API-only beta (context-1m-2025-08-07 header) — not available to Claude Code CLI users, including Max 20x subscribers.

This mismatch caused 10+ session crashes in a single day during heavy coding work.

The Problem

1. Misleading expectations: Updating to get Opus 4.6 implies 1M context is available. The /context command shows "200K max" but users don't know that's the hard limit — they assume it's a display bug (see [Bug] /context command reports 200K max for Claude Opus 4.6 instead of 1M #23432).
2. No graceful degradation: When context approaches 200K, the session crashes without warning. No suggestion to compact, no error message — just a dead session.
3. s1mAccessCache.hasAccess = false for Max 20x subscribers — the 1M beta requires API tier 4 billing, which is a separate track from Max subscriptions. There's no way for Max users to opt in.
4. Auto-compaction races the limit: Evidence of 1.8MB+ session JSONL files that crashed without compaction summaries, suggesting auto-compact either didn't trigger or didn't complete before the context limit was hit.
5. Workflow damage: Users who build session management around "1M context" (identity docs, wake protocols, large context reads) unknowingly burn through 200K in 30-45 minutes of heavy tool use.

Steps to Reproduce

1. Subscribe to Max 20x plan
2. Update Claude Code to latest (2.1.34+)
3. Select Opus 4.6 as model
4. Work on a heavy session with many tool calls (file reads, bash commands, etc.)
5. Session crashes at ~200K tokens without warning

Expected Behavior

Either:

• Ship 1M context for Claude Code Max users (preferred — we're paying $200/month), or
• Clearly communicate the 200K limit everywhere: update notes, /context output, model selector, and ensure auto-compact triggers reliably well before the limit with a visible warning

Environment

• Claude Code: 2.1.34
• Model: claude-opus-4-6
• Plan: Max 20x ($200/mo)
• OS: Ubuntu 24.04 (Linux VM)

Related Issues

• [Bug] /context command reports 200K max for Claude Opus 4.6 instead of 1M #23432 — /context reports 200K max for Opus 4.6
• Feature Request: Enable 1M Context Window for Claude Code #5644 — Feature request for 1M context in Claude Code

[github-actions]

Found 3 possible duplicate issues:

1. [BUG] Opus 4.6 with [1m] context window returns "long context beta not available" on Max subscription #23472
2. [Bug] Anthropic API Error: Long context beta unavailable for Max plan with Claude Opus 4.6 1M #23700
3. [Bug] /context command reports 200K max for Claude Opus 4.6 instead of 1M #23432

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
• To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code