OpenProse

OpenProse is an open-source operating system for reliable long-running AI agents. Instead of scripting brittle prompt chains, developers write structured Markdown contracts - *.prose.md files - that declare the world state an agent should maintain. A reactive runtime figures out the work needed to get there, and the same program runs unchanged across Claude Code, Codex, OpenCode, and Amp. Founded in 2026 by Dan Barrett and backed by Y Combinator's Spring 2026 batch.