Anthropic's CI Scaled 25x in Six Months

AI-assisted coding at Anthropic has driven an 8x increase in code shipped per engineer, with Claude authoring 80% of it. This caused a 25x surge in CI jobs over six months and a 10x growth in tests, repeatedly overwhelming their test impact analysis service despite multiple quick fixes. After three successive patches lasting 70 days, 29 days, and less than one day respectively, the team overhauled their architecture entirely, moving from a single-process system to a horizontally sharded design. The key lesson: plan for exponential growth, not linear, as agentic coding makes full architectural redesigns faster and more necessary than ever.