Autonomous agents re-feed context every step — watch the token bill explode.
The token bill compounds because accumulated context is re-billed each loop — a 10-step agent can cost 20–40× a one-shot call. Break down a single chat on the chatbot cost calculator, and make sure the growing context fits on the context window calculator.
Free AI agent cost calculator — model how an autonomous agent that re-sends accumulating context each step turns a simple task into a large token bill.
Agents run in a loop, and each step re-sends the growing history — system prompt, prior reasoning and every tool result so far. That accumulated context is billed as input again on every step, so a multi-step task costs several times more than a single call, even before counting the extra output.
Summarise or truncate the scratchpad instead of carrying full history, cap the number of steps, prune verbose tool outputs before feeding them back, cache the stable system prompt, and use a cheaper model for routine steps. The lever is the re-sent context, which grows every step.