diff --git a/.gitattributes b/.gitattributes
index db0630e..9e60f11 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -15,3 +15,7 @@ graphify-out/graph.html -diff
 *.css text eol=lf
 *.json text eol=lf
 *.md text eol=lf
+*.sh text eol=lf
+
+# Git hooks must stay LF — a CRLF shebang breaks the interpreter.
+scripts/git-hooks/* text eol=lf
diff --git a/CLAUDE.md b/CLAUDE.md
index f449b67..b06b361 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -1,3 +1,9 @@
+## Branching (MANDATORY)
+
+`main` is protected: direct pushes are blocked (GitHub branch protection, admins included) and merging requires a PR with the Claude BugBot check green. Never commit feature work straight to `main` — branch, push the branch, open a PR, let it merge.
+
+After a fresh clone, install the local hooks once: `sh scripts/install-git-hooks.sh`. It adds a `pre-push` guard (rejects direct pushes to main before the round-trip) alongside graphify's hooks. Emergency bypass is `git push --no-verify`; the server rule still catches it.
+
 ## graphify
 
 This project has a graphify knowledge graph at graphify-out/.
diff --git a/scripts/git-hooks/pre-push b/scripts/git-hooks/pre-push
new file mode 100644
index 0000000..d1229a1
--- /dev/null
+++ b/scripts/git-hooks/pre-push
@@ -0,0 +1,27 @@
+#!/bin/sh
+# Refuse direct pushes to the protected branch. Feature work goes via a PR.
+# Server-side branch protection also enforces this; this hook is the fast,
+# local first line of defence so you find out before the round-trip.
+#
+# Bypass for a genuine emergency (rare): git push --no-verify
+#
+# Installed into .git/hooks/pre-push by scripts/install-git-hooks.sh.
+
+protected="refs/heads/main"
+
+while read -r local_ref local_sha remote_ref remote_sha; do
+  if [ "$remote_ref" = "$protected" ]; then
+    echo "" >&2
+    echo "BLOCKED: direct push to main is not allowed." >&2
+    echo "  Branch, push that, and open a PR:" >&2
+    echo "    git switch -c feat/your-change" >&2
+    echo "    git push -u origin feat/your-change" >&2
+    echo "    gh pr create" >&2
+    echo "" >&2
+    echo "  (Real emergency only: git push --no-verify)" >&2
+    echo "" >&2
+    exit 1
+  fi
+done
+
+exit 0
diff --git a/scripts/install-git-hooks.sh b/scripts/install-git-hooks.sh
new file mode 100644
index 0000000..75a45c4
--- /dev/null
+++ b/scripts/install-git-hooks.sh
@@ -0,0 +1,19 @@
+#!/bin/sh
+# Install this repo's tracked git hooks into .git/hooks without disturbing
+# hooks other tools manage there (e.g. graphify's post-commit/post-checkout).
+# Run once per clone:  sh scripts/install-git-hooks.sh
+
+set -e
+
+repo_root=$(git rev-parse --show-toplevel)
+src="$repo_root/scripts/git-hooks"
+dst="$repo_root/.git/hooks"
+
+for hook in "$src"/*; do
+  name=$(basename "$hook")
+  cp "$hook" "$dst/$name"
+  chmod +x "$dst/$name"
+  echo "installed: .git/hooks/$name"
+done
+
+echo "Done. Direct pushes to main will now be blocked locally."