diff --git a/.learnings/ERRORS.md b/.learnings/ERRORS.md
index 6349d9e2d..f05167b91 100644
--- a/.learnings/ERRORS.md
+++ b/.learnings/ERRORS.md
@@ -66,3 +66,10 @@ Recover host first, stop residual build/runner tasks, verify production/staging
 - Error: sh/bash command not found in the PowerShell runtime.
 - Fix: run POSIX shell syntax checks via an available Linux host/container, e.g. scp to xiaoxia-server and run sh -n on a temporary file.
 
+
+## 2026-06-25 - Protected main release must not be direct-merged locally
+
+- Failed action: attempted local develop->main merge and tag push for v0.1.51.
+- Errors: main branch is protected from direct push; local main had divergence/conflicts; tag v0.1.51 was pushed from the wrong local main HEAD and then removed.
+- Fix: never tag production before protected main has accepted the release commit. Use PR/approved merge path or Gitea API merge, then tag the actual merged main commit.
+