Converting provider streams into typed events before tool calls hit the world was faster than serializing them, not slower

arXiv 2608.25322·low signalXBlueskyLinkedInCopy link

Metis is a multi-provider runtime that turns model output streams into typed events and makes permission decisions, interference classes, terminal results and lifecycle transitions explicit before an admitted call produces an external effect. The counterintuitive result: across 30 matched real-I/O pairs, four-class mediation cut median elapsed time from 25.958ms under forced serialization to 14.146ms, faster in every single pair (mean paired difference -12.295ms, 95% bootstrap [-12.968, -11.694]). In a child-boundary ablation the full gate-plus-registry condition blocked the declared unauthorized effect and hid all five escape tools; removing both protections reversed both results.