Copilot CLI 1.0.83 makes multi-model routing declarative, and enforceable.

Released September 4, custom agents can name several models in model, tried in order until one is available, with model-policy: required keeping model changes on that list. This is the first mainstream agent CLI where heterogeneous routing is config rather than a wrapper script, and the policy flag is what makes it usable in a team, because it stops someone silently moving a cost-sensitive agent onto a frontier model. The same release stops enterprise-denied MCP servers starting before the managed allow/deny policy resolves, closing a race that gave denied servers a window at every launch (GitHub).