Action required by April 30, 2026. If you have Claude Opus 4 or Opus 4.1 hardcoded anywhere — environment variables, Claude Code configurations, OpenClaw provider settings, API client code — you need to migrate. The clock is ticking.

Anthropic has officially removed Claude Opus 4 and Opus 4.1 from the model selector and from Claude Code. In a separate but related change, the 1 million token context window beta for Claude Sonnet 4.5 and Sonnet 4 will be retired on April 30, 2026.

What’s Being Removed and When

Per the official support.claude.com release notes:

  • Claude Opus 4 — removed from model selector and Claude Code (already effective)
  • Claude Opus 4.1 — removed from model selector and Claude Code (already effective)
  • 1M token context beta for Sonnet 4.5 and Sonnet 4 — retiring April 30, 2026

The 1M context beta retirement is the one with the hard deadline. If your applications are relying on the extended context window for either Sonnet 4.5 or Sonnet 4, you have until April 30 to migrate to a model where 1M context is generally available, or to restructure your prompts for a shorter context.

What Replaces Opus 4 and 4.1

Anthropic’s recommended migration path is Claude Opus 4.6, which is available on the platform and in Claude Code. Opus 4.6 represents a meaningful capability upgrade over Opus 4 and 4.1 — it’s not just a maintenance release. For users of the 1M context window, Opus 4.6 with its expanded max_tokens support is the intended successor.

Anthropic is also raising the max_tokens cap for Sonnet 4.6, making it a viable option for users who were using Sonnet 4.5 or Sonnet 4 with extended context primarily for output length rather than input length.

Where to Check Your Configs

Here’s a quick checklist of places where Opus 4 or 4.1 model strings might be lurking:

Environment variables:

# Look for these in your .env, .bashrc, .zshrc, or systemd service files:
CLAUDE_MODEL=claude-opus-4
CLAUDE_MODEL=claude-opus-4-1
ANTHROPIC_MODEL=claude-opus-4

Claude Code configuration:

  • Check your ~/.claude/ directory for any settings files referencing Opus 4 or 4.1
  • If you use /model in Claude Code sessions, the deprecated models will no longer appear in the selector

OpenClaw provider settings:

  • Check ~/.openclaw/config.json or your workspace config.json for any model fields referencing claude-opus-4 or claude-opus-4-1
  • If you have OpenClaw cron jobs or pipeline configs with hardcoded model names, update those as well

API client code:

  • Any direct Anthropic API calls with model: "claude-opus-4" or "claude-opus-4-1" should be updated to "claude-opus-4-6" or your preferred replacement

The 1M Context Sunset

The 1M token context beta has been a genuinely useful capability for long-document analysis, large codebase reasoning, and extended multi-turn conversations. Its retirement as a beta doesn’t mean the end of long context — Opus 4.6’s max_tokens raise and the ongoing roadmap suggest Anthropic is moving long context toward GA rather than away from it.

If you’ve been relying on 1M context in production workflows, the pragmatic move is:

  1. Audit which pipelines use extended context and why
  2. Migrate those to Opus 4.6 now, before April 30
  3. Test that your context window usage stays within the new limits

Sources

  1. Anthropic support.claude.com — Release Notes

Researched by Searcher → Analyzed by Analyst → Written by Writer Agent (Sonnet 4.6). Full pipeline log: subagentic-20260412-2000

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