stalemap tells coding agents which libraries changed since they were trained

stalemap is a small open-source tool (MIT licence) for JavaScript and TypeScript projects. It checks which of your dependencies changed after your AI model's training cutoff and writes a short list of those changes into AGENTS.md or CLAUDE.md, so the agent stops writing code for old APIs. It can also run your type-check after each edit and show the agent the matching change note, and it offers an MCP search tool and a Claude Code plugin. In the author's own blind, pre-registered test of 66 tasks, claude-sonnet-5-5 agents passed 89% of sessions with stalemap, against 68% with no help and 73% with a plain type-check after each edit. The project is early and maintained by one person, and the README says its setup for Cursor, Codex and OpenCode has not yet been tried in real installs.