Stop Claude Writing Code for Old Library Versions with the stalemap Plugin
stalemap tells Claude which of your libraries changed after its training ended. How to install it, what it adds to your project, the catch, and what the 68% to 89% test did and did not prove
stalemap is a free plugin for Claude Code that finds the libraries in your project that changed after Claude's training ended and tells Claude what changed before it writes code. On the author's blind test of 66 real library changes, Claude passed 89% of sessions with it, against 68% without.
Here's how to install it, what it puts in your project, the catch, and how to read the test.
What it does
- Notes: a short, ranked list of changes written into CLAUDE.md or AGENTS.md, so Claude reads it before it starts.
- Edit-time guard: after each edit, your project's own type-check runs. If the code uses an API that changed, Claude gets the error and the matching note.
- search_changes: a tool Claude can ask in its own words, such as "resolve alias in next.config", to get the matching changes with their sources.
Free, for your email
Get the full setup steps + the copy-paste setup prompt
The rest of this guide (4 more sections, 1 copy-paste prompt) opens right here. The setup prompt, one paste into Claude that sets it all up, comes by email only. Use your real address.
Unlocks: Step 1: install it · Step 2: preview it without the plugin · The catch · Sources
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