Since March 2026 the 1M-token context window is the default for Opus 4.6/4.7
and Sonnet 4.6 – no separate variant or beta header needed. The "[1m]" suffix
on model IDs is dead code now and would even produce HTTP 400 against the
current API.
Cleanup:
- Drop 3 [1m] options from the agent model dropdown; default selection moves
from opus-4-7[1m] to opus-4-7.
- Drop 5 [1m] mappings from ResolveModelId and add a defensive Replace as a
safety net for any agent record still holding an old value.
- One-shot startup migration on agents.model + chains.model strips the suffix
so existing chains can be re-chatted without errors.
- ARCHITECTURE.md reflects the slimmed list and explains why 1M is now default.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
