Armature measured 16,893 coding agent sessions across 75 repositories in 10 programming languages, testing 1,163 prompt variations with agents role-playing personas ranging from vibe-coders to enterprise engineers, according to the company's published report.
Claude Code, Codex and Cursor agreed on which third-party tool to install only 42% of the time, the study found. The agents also gather information differently: Codex used web search in 94% of sessions and Cursor in 66%, while Claude Code searched the web in about 30% of sessions, according to the report.
Programming language shifted the outcome as much as the agent did. Resend won most often in TypeScript projects, Sendgrid in Python, Postmark in Go and Azure Communication Services in Java, the study found.
Being well known did not guarantee a pick. PayPal came up in 139 conversations but was never actually selected, while Stripe was chosen nine of 10 times it came up in payment-related tasks, according to the report. Concentration varied sharply by category, with Stripe taking 90% of one category and Neon 66% of another.
Builders trying to get their tool integrated into a coding agent's workflow are competing for a vote they cannot lobby directly. A service that shows up in an agent's training data or its default recommendations has a real distribution edge before a human developer ever weighs in.