diff --git a/.githooks/commit-msg b/.githooks/commit-msg
new file mode 100755
index 0000000..4bf8b55
--- /dev/null
+++ b/.githooks/commit-msg
@@ -0,0 +1,52 @@
+#!/usr/bin/env bash
+#
+# commit-msg: enforce the project's commit subject style.
+#
+# The subject (first line) MUST be:   VERB - Short description
+#   - VERB : an ALL-CAPS verb, >= 3 letters
+#            (e.g. ADDED, FIXED, STYLED, DOCUMENTED, CLEANED, REVERTED,
+#             CONFIGURED, IMPROVED, POLISHED, REMOVED, RENAMED, REFACTORED)
+#   - then " - " (space hyphen space)
+#   - then a description (capitalized, imperative, no trailing period).
+#
+# Good:
+#   FIXED - Load .env in drizzle.config so drizzle-kit targets the right DB
+#   STYLED - Turn the admin portfolio overview into a professional table
+#
+# Bad (rejected):
+#   Flatten portfolio category routes to /portfolio/[slug]   (no VERB prefix)
+#   feat(hero): add ambient backdrop                          (wrong style)
+#
+# Install once:   git config core.hooksPath .githooks
+# Emergency skip: git commit --no-verify
+#
+set -euo pipefail
+
+msg_file="$1"
+
+# First non-empty, non-comment line = the subject.
+subject="$(grep -vE '^[[:space:]]*#' "$msg_file" | grep -vE '^[[:space:]]*$' | head -n1 || true)"
+
+# Let git's own housekeeping commits through untouched.
+case "$subject" in
+  Merge\ * | Revert\ * | fixup!\ * | squash!\ *) exit 0 ;;
+esac
+
+pattern='^[A-Z]{3,} - .+'
+if [[ ! "$subject" =~ $pattern ]]; then
+  cat >&2 <<EOF
+
+✗ commit rejected: subject does not match the project style.
+
+  Required:  VERB - Short description
+  Example:   FIXED - Load .env so drizzle-kit targets the right DB
+
+  Your subject was:
+    ${subject:-(empty)}
+
+  VERB must be ALL-CAPS (>= 3 letters), then " - ", then the description.
+  (Emergency skip: git commit --no-verify)
+
+EOF
+  exit 1
+fi
diff --git a/CLAUDE.md b/CLAUDE.md
index 19b8e97..167d351 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -125,4 +125,30 @@ SITE_RUNTIME_ORIGIN       Internal origin for middleware to fetch runtime state
 - If a task may affect routing, auth, i18n, or runtime config, inspect `proxy.ts`, `lib/admin-routing.ts`, `i18n/routing.ts`, and the relevant `lib/app-config.ts` modules first.
 - For schema or database changes, inspect the Drizzle schema (`lib/db/schema.ts`), the drizzle-kit migration flow, and migration impact before editing.
 - Ask before performing large refactors, file moves, destructive changes, or broad formatting changes.
-- When updating behavior, also update docs/specs if the change affects public behavior, business rules, or architecture.
\ No newline at end of file
+- When updating behavior, also update docs/specs if the change affects public behavior, business rules, or architecture.
+
+## Git commit messages (MANDATORY)
+
+Every commit subject **must** follow this exact style, or the `commit-msg` hook
+(`.githooks/commit-msg`) will reject the commit:
+
+```
+VERB - Short description
+```
+
+- `VERB` is an ALL-CAPS verb, at least 3 letters — e.g. `ADDED`, `FIXED`,
+  `STYLED`, `REMOVED`, `RENAMED`, `REFACTORED`, `IMPROVED`, `DOCUMENTED`,
+  `CLEANED`, `REVERTED`, `CONFIGURED`, `POLISHED`.
+- Then exactly `" - "` (space, hyphen, space).
+- Then a capitalized, imperative description with no trailing period.
+
+Good: `FIXED - Load .env in drizzle.config so drizzle-kit targets the right DB`
+Bad (rejected): `Flatten portfolio category routes` — no `VERB` prefix.
+Bad (rejected): `feat(hero): add backdrop` — Conventional Commits is NOT used here.
+
+Do **not** add any `Co-Authored-By` / "Generated with Claude Code" attribution
+lines to commits in this repo. Write the body (when useful) as wrapped prose or
+bullet points explaining the *why*, matching the existing history.
+
+The hook and the test gate are activated per clone with:
+`git config core.hooksPath .githooks` (emergency skip: `git commit --no-verify`).
\ No newline at end of file