One API for qualified, cost-aware model routing.
Send a request to muscle/auto. Flex checks what the task needs, excludes routes that can't meet it, then chooses a qualified route for speed, reasoning, tools and cost.
At a glance
- Status
- Invite-only beta
- Works with
- Supported SDKs and coding agents
- Model id
muscle/auto- Billing
- Prepaid credits
All products
Checks first. Then the route.
Qualification first
Routes that can't meet the request are out.
Flex first excludes routes that can't meet the request's hard requirements: tool shape, streaming, context, account policy and funding. Only then does it compare the rest.
The right route for the work
Different tasks need different strengths.
A quick explanation, a tool-heavy search and a multi-file repair reward different models. Flex chooses for the task and the workflow.
New models earn their place
Tested on agent workflows before they join.
We test new models and provider paths against real agent workflows before they enter the roster, so your team can skip the release watching.
Your tools stay yours
Flex returns tool calls. Your app runs them.
Supported streams, tool calls and continuations stay in your agent. Your application keeps its tools and its approvals.
Prepaid with a hard stop
Spend can't run past your balance.
Credits are held before a charged request is routed. When the balance can't cover it, Flex declines new work instead of running up a bill.
How it works
How Flex chooses a route.
Quickstart
Keep your agent. Change one endpoint.
Beta pricing
Prepaid, with a hard stop.