What Are AI Agents? Autonomy You Have to Pay For

"Agent" is used to mean anything from a chatbot with tools to a system that runs for an hour unsupervised. The definition that matters commercially is narrower: an agent is software that takes a multi-step task and completes it without you driving each step, and charges you for what it consumes along the way. That second half is the part that changes a budget.

Manus is the clearest example of the open-ended kind, free to try with Plus at $39/mo and Pro from $199/mo. Our catalog records two limits that follow directly from how it is priced: credits are metered by task complexity and duration, so a long agent run is unpredictable before you start it, and complex tasks take a while. It also records that Manus is not for budget-limited one-off tasks or workflows that must be fully controllable and reproducible — which is the honest summary of the category. Coze is the bounded alternative: free with Premium from $9/mo, and its features are bot building, plugins, workflows and a knowledge base, which is what you want when the task is repetitive and you would rather define it once than let an agent interpret it. Codex (Plus $20/mo, Pro $200/mo) and ChatGPT (free, Plus $20/mo) bring the same pattern to code and to general work.

The trade is straightforward once stated: an agent is worth paying for when the task is variable and you cannot predict the steps, and it is a worse deal than a scheduled script the moment the task is routine. Our catalog says as much about Manus — it suits occasional jobs and punishes routine volume — and the same logic applies to any consumption-metered agent, because a loop that retries costs money each time it retries. Two further limits to plan around: complex runs take minutes to hours rather than seconds, so nothing with a deadline in seconds belongs here, and reproducibility is the thing you give up, because an agent choosing its own steps will not choose them identically twice.