Claude now writes more than 80% of Anthropic's merged code

Anthropic published unusually concrete internal evidence of how deeply coding agents have changed its engineering workflow. As of May 2026, Claude authored more than 80% of the code merged into Anthropic's production codebase, up from low single digits before Claude Code launched in February 2025. The company says its typical engineer now merges eight times as much code per day as in 2024, although it cautions that lines of code overstate true productivity. Claude's success rate on Anthropic's most open-ended engineering tasks reached 76% in May, and an automated Claude reviewer now checks proposed changes before merge. This is a high-signal adoption milestone because it measures production usage inside a frontier lab, while also showing the new bottleneck: human judgment, review capacity, and deciding which problems are worth solving.

Key details: June 4, 2026, More than 80% of merged production code, 8x code merged per engineer per day versus 2024, 76% success on open-ended tasks, Anthropic Institute.

Continue swiping for more AI Brief stories.