If there are millions of lines on github in your language.
Otherwise the 'teaching AI to write your language' part will occupy so much context and make it far less efficient that just using typescript.
The vast majority of tokens are not used for documentation or reference material but rather are for reasoning/thinking. Unless you somehow design a programming language that is just so drastically different than anything that currently exists, you can safely bet that LLMs will pick them up with relative ease.
You can do it today if you are willing to pay (API or on top of your subscription) [0]
> The 1M context window is currently in beta. Features, pricing, and availability may change.
> Extended context is available for:
> API and pay-as-you-go users: full access to 1M context
> Pro, Max, Teams, and Enterprise subscribers: available with extra usage enabled
> Selecting a 1M model does not immediately change billing. Your session uses standard rates until it exceeds 200K tokens of context. Beyond 200K tokens, requests are charged at long-context pricing with dedicated rate limits. For subscribers, tokens beyond 200K are billed as extra usage rather than through the subscription.
[0] https://code.claude.com/docs/en/model-config#extended-contex...