diff --git a/README.md b/README.md
index fb21cf8..48733e0 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,7 @@
 # Spectra
 
+> **Archived — no longer maintained (2026-09-24).** This repository is read-only and has no replacement.
+
 <p align="center">
   <img src="https://mark.sylphx.com/api/v1/banner?type=orbit&theme=tokyonight&text=spectra&desc=Transform+Dart+data+classes+into+JSON+Schema%2C+OpenAPI%2C+and+Protocol+Buffers.+Wor&height=200&animation=rise&credit=0" alt="spectra — Sylphx Mark banner" width="100%" />
 </p>