[BUG] Desktop app Code tab routes Sonnet 4.6 sessions to 1M context, blocking usage on Max plan

App version: 1.8555.2 (a476c3) — 2026-05-22
Plan: Max 20x ($200/month)
Platform: macOS, Claude desktop app (Code tab)

What's wrong

Selecting Sonnet 4.6 (standard 200K) via the model picker immediately fails with a 1M context credits error on a brand new session with a trivial task. The model picker shows Sonnet 4.6 with a checkmark, and no 1M variant is listed. Despite this, the session is silently routed to the 1M context variant, which requires usage credits on Max plan.

Error message

Usage limit reached
You've reached your usage limit. Try again after your limit resets.

API Error: Usage credits required for 1M context · turn on usage credits at claude.ai/settings/usage, or use --model to switch to standard context

Steps to reproduce

1. Open Claude desktop app, navigate to Code tab
2. Start a new session
3. Open model picker — select Sonnet 4.6 (checkmark confirms; no 1M variant shown)
4. Set effort to Medium
5. Send any prompt, including trivial tasks well within 200K context
6. Observe immediate 1M context credits error

Expected behavior

Selecting Sonnet 4.6 (standard) routes the session to the 200K context model. No usage credits required.

Actual behavior

Session is silently routed to Sonnet 4.6[1m] despite no 1M selection in the picker. Error fires immediately. Misleading "usage limit reached" banner appears. Account weekly usage was ~1% at time of error.

Workaround

Switching to Opus 4.7 (not 1M) resolves the issue, confirming this is an entitlement/routing bug specific to Sonnet 4.6 in the desktop app Code tab.

Related issues

#58730 #45847 #45390 #29301