diff --git a/CHANGELOG.md b/CHANGELOG.md
index 538cdba76..5ed5fc80a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ Format based on [Keep a Changelog](https://keepachangelog.com/).
 ## [Unreleased]
 
 ### Added
+- Sprint 12 "Build" briefings — 50 tickets across server, client, copy, visual, ci teams; production-layer foundations + all v0.1 copy authoring
 - `.tmp/` gitignored repo directory for agent temp files — avoids Bash permission prompts during PR review comment posting
 - `sed -n` blanket permission in shared settings