Statusline reports 200K context window despite v2.1.76 banner announcing 1M

Summary

Claude Code v2.1.76 displays the banner:

↑ Opus now defaults to 1M context · 5x more room, same pricing

However, the context_window_size field in the statusline JSON payload still reports 200000 (200K), not 1000000 (1M).

Reproduction

1. Upgrade to Claude Code v2.1.76 (brew upgrade claude-code)
2. Start a new session with Opus 4.6
3. Configure a statusline command that dumps the JSON stdin to a file
4. Observe context_window.context_window_size: 200000

Statusline JSON (trimmed)

{
  "model": { "id": "claude-opus-4-6" },
  "context_window": {
    "context_window_size": 200000,
    "used_percentage": 30,
    "exceeds_200k_tokens": false
  }
}

Expected

context_window_size should be 1000000 if the banner advertises 1M context for Opus 4.6.

Environment

• Claude Code v2.1.76
• macOS Darwin 25.2.0
• Model: claude-opus-4-6 (Claude Max)