Which vendor does your coding agent actually pick?

Armature, which discloses that it sells growth services to developer tools, ran nearly 17,000 sandboxed sessions across 75 synthetic repositories, three coding agents, and four simulated user personas, then tracked which third-party service each agent picked for tasks like storage, payments, or email. All three agents agreed on a winner in only 42 percent of cases. Claude Code relied on its own priors and searched the web in about 30 percent of sessions, while Codex searched the web in 94 percent of sessions, usually narrowing results with site: operators. Mentions did not predict wins: PayPal came up in 139 sessions in the payments category and was picked zero times, and Supabase was the most-mentioned database at 242 mentions but still lost most matchups to Neon. The identical task, run in four different programming languages, produced four different winning email providers. Armature published its full session traces and a leaderboard alongside the post.

Why it matters: If a coding agent recommends a database or payment provider, the recommendation may reflect training priors and vendor documentation more than an evaluation of your actual constraints. Teams should inspect the agent's stated reasoning before accepting the pick, especially in a language or stack outside its strongest priors.