diff --git a/CLAUDE.md b/CLAUDE.md
index 254d0e9..f224054 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -1,3 +1,9 @@
 # Claude Code Rules
 
 Always read and respect [docs/DEV.md](docs/DEV.md) at the start of every conversation before doing any work in this project.
+
+After every code change, update the relevant documentation. This includes:
+- `docs/` for cross-cutting conventions, architecture decisions, and design rules
+- co-located `README.md` files in `src/core/<module>/` and `src/features/<feature>/` for module-level behaviour
+
+No task is complete until all impacted documentation is up to date.