legion-llm

https://github.com/LegionIO/LegionIO

A proxy between AI clients and model backends. Requests translate once to a canonical form, route to the cheapest capable tier (local, direct, fleet, cloud, frontier), and escalate on failure with circuit breakers and mid-stream failover. A post-turn Curator bounds long agent sessions (97.7% context reduction vs naive resend at 50+ turns, production-measured). Provider adapters are separate lex-llm-* gems.