A large context window in Claude Code feels free, and it is the opposite. Every token you load is re-billed on every turn after. The prompt cache that should make that cheap expires in five minutes, turning a tenth-price read into a higher-price write. And accuracy fades as the window fills. Here is the real cost.
Claude Code effort mode looks like a cost dial: turn it down to spend fewer tokens. The official docs say otherwise. Effort is a behavioral signal, not a strict budget, so low effort does not reliably cut spend and can quietly raise it. Here are the five levels, where they stop, and how to set effort with intent.
A surprising Claude Code bill is almost never one big expense. It is four different cost shapes stacked up: a context window that bills every turn, subagents that each cost a fixed chunk, skills that cost almost nothing until used, and caching that can cut the recurring cost or not. Budgeting tokens means knowing the four shapes.