Enabling /extra-usage in my (personal) claude code[0] with this env:

    "ANTHROPIC_DEFAULT_SONNET_MODEL": "claude-sonnet-4-6[1m]"

Fixed a UI issue I had yesterday in a web app very effectively using claude in chrome. Definitely not the fastest model - but the breathing space of 1M context is great for browser use.

[0] Anthropic have given away a bunch of API credits to cc subscribers - you can claim them in your settings dashboard to use for this.