Basics
Models & limits
Pick the right Claude model and understand what it can and can't hold in mind.
Knowledge cards
Concept
Know What Actually Fits in the Context Window
A working understanding of the context window: the finite budget of tokens Claude can attend to at once, shared across the system prompt, everything you've pasted, the conversation history, and the space left for the reply. It is short-term working memory, not permanent storage.
Best practice
Match the Claude Model to the Task, Not the Hype
A habit of choosing the Claude model by what the task actually demands — a smaller, faster model for simple high-volume work, the most capable model for hard reasoning — rather than defaulting to the biggest one for everything or the cheapest one to save money.