Yesterday we mapped Anthropic's ten finance agent templates — Pitch builder, KYC screener, Earnings reviewer, the whole org-chart of an investment bank packaged as Claude Cowork plugins, Claude Code plugins, and Managed Agents cookbooks. That piece was the closed-source enterprise side of the buy-vs-build call. This piece is the open-source companion: the structural buyer's guide for the team that already decided "we're not putting our deal flow inside someone else's tenant." There is exactly one open-source project on GitHub today that goes head-to-head with the research half of Anthropic's lineup. It's virattt/dexter — 24.4k stars, 3.0k forks, MIT license, TypeScript 99.4% , and a self-description that telegraphs the positioning: "Think Claude Code, but built specifically for financial research." The latest release ( v2026.5.1 ) shipped May 1 — four days before Anthropic's launch. The collision is intentional. View Dexter on GitHub → This piece is the job-by-job comparison for the self-host buyer.…