A bot, an agent, and an internal tool should not share one uncapped key.
Use cases
A ceiling for the app, not the invoice.
Support bots, coding agents, internal assistants, and apps that call more than one model vendor. Each one is a Fuse project with its own keys and its own stop.
The bill is not the only place spend shows up.
By the time the provider dashboard moves, the traffic already happened. Fuse is in front of that call.
The model name decides which provider key goes out. The ceiling is still one number.
A 402 is the product. The request does not reach the provider.
Four places a ceiling earns its keep.
Support bots
Stop a busy support week from emptying the provider account.
The bot keeps answering until the ceiling you set. The next request after that is a 402, and the provider is not called.
Coding agentsGive each agent a budget it cannot walk past.
Retries and long-context models add up. One Fuse project per agent means a loop spends only what you allowed.
Internal toolsA company assistant with a ceiling the owner can see.
People keep their provider accounts. Fuse only meters the traffic you choose to send through one project.
Several vendorsOne ceiling across every model vendor you call.
OpenAI, Anthropic, Google, Mistral, xAI, or a gateway you add. The model name picks the key. The project ceiling is in dollars.