Agentic Coding Is Straining CI. Here's How We Scaled Test Impact Analysis at Anthropic

2026-09-15

Agentic coding drove a 25x increase in CI jobs over six months, overwhelming a singleton test selection service despite bigger machines, package sharding, and daily restarts. Anthropic replaced it with stateless listener workers, a journal in an in-memory store, and a separate rollup consumer, creating a horizontally scalable system that has remained stable.