diff --git a/.ssh/config b/.ssh/config
index 51d1059..ed1c6f8 100644
--- a/.ssh/config
+++ b/.ssh/config
@@ -4,3 +4,13 @@ Host github.com
     User git
     IdentityFile ~/.ssh/github_ed25519
     IdentitiesOnly yes
+    # git push opens this connection BEFORE running the pre-push hook, then
+    # leaves it fully idle for the hook's entire duration. Found 2026-08-29:
+    # under heavy concurrent machine load (~80 sessions), hooks routinely ran
+    # long enough that GitHub's idle-connection timeout killed the SSH session
+    # while the hook was still running — the push then silently failed to
+    # transfer after printing "Safe to push," with only a stray "Connection to
+    # github.com closed by remote host." in the log to explain it. Active
+    # keepalives during that idle window prevent the drop.
+    ServerAliveInterval 30
+    ServerAliveCountMax 10