The context window isn't "crippled".

Create a markdown document of your task (or use CLAUDE.md), put it in "plan mode" which allows Claude to use tool calls to ask questions before it generates the plan.

When it finishes one part of the plan, have it create a another markdown document - "progress.md" or whatever with the whole plan and what is completed at that point.

Type /clear (no more context window), tell Claude to read the two documents.

Repeat until even a massive project is complete - with those 2 markdown documents and no context window issues.