Add these settings to your `.claude/settings.json`:

     ```json
     {
       "env": {
         "ANTHROPIC_CUSTOM_HEADERS": {"anthropic-beta":
     "context-1m-2025-08-07"},
         "ANTHROPIC_MODEL": "claude-sonnet-4-20250514",
         "CLAUDE_CODE_MAX_OUTPUT_TOKENS": 8192
       }
     }
     ```