diff --git a/.claude/hooks/check-gstack.sh b/.claude/hooks/check-gstack.sh
new file mode 100644
index 0000000..2ade7db
--- /dev/null
+++ b/.claude/hooks/check-gstack.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+# Block skill usage when gstack is not installed globally.
+
+if [ ! -d "$HOME/.claude/skills/gstack/bin" ]; then
+  cat >&2 <<'MSG'
+BLOCKED: gstack is not installed globally.
+
+gstack is required for AI-assisted work in this repo.
+
+Install it:
+  git clone --depth 1 https://github.com/garrytan/gstack.git ~/.claude/skills/gstack
+  cd ~/.claude/skills/gstack && ./setup --team
+
+Then restart your AI coding tool.
+MSG
+  echo '{"permissionDecision":"deny","message":"gstack is required but not installed. See stderr for install instructions."}'
+  exit 0
+fi
+
+echo '{}'
diff --git a/.claude/settings.json b/.claude/settings.json
new file mode 100644
index 0000000..13181ed
--- /dev/null
+++ b/.claude/settings.json
@@ -0,0 +1,15 @@
+{
+  "hooks": {
+    "PreToolUse": [
+      {
+        "matcher": "Skill",
+        "hooks": [
+          {
+            "type": "command",
+            "command": "\"$CLAUDE_PROJECT_DIR/.claude/hooks/check-gstack.sh\""
+          }
+        ]
+      }
+    ]
+  }
+}
diff --git a/CLAUDE.md b/CLAUDE.md
index 314ba32..791af13 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -68,3 +68,9 @@ The `Sesiune` column is computed by `_f_session` from `Data` + `Ora RO` (Romania
 - The user is **Marius**, a discretionary trader doing his own backtest, not an engineer building a product. Prefer minimal, legible changes to the Excel template over abstractions. The audience is one person logging trades, not a team.
 - When changing formulas in `generate_template.py`, regenerate the workbook and inspect at least one row's outputs before declaring done — a formula typo silently breaks the entire downstream Dashboard.
 - The git user is `Marius` on branch `master` (not `main`); PRs are not the workflow here, direct commits to `master` are.
+
+## gstack
+
+Use the `/browse` skill from gstack for all web browsing. Never use `mcp__claude-in-chrome__*` tools.
+
+Available gstack skills: `/office-hours`, `/plan-ceo-review`, `/plan-eng-review`, `/plan-design-review`, `/design-consultation`, `/design-shotgun`, `/design-html`, `/review`, `/ship`, `/land-and-deploy`, `/canary`, `/benchmark`, `/browse`, `/connect-chrome`, `/qa`, `/qa-only`, `/design-review`, `/setup-browser-cookies`, `/setup-deploy`, `/setup-gbrain`, `/retro`, `/investigate`, `/document-release`, `/document-generate`, `/codex`, `/cso`, `/autoplan`, `/plan-devex-review`, `/devex-review`, `/careful`, `/freeze`, `/guard`, `/unfreeze`, `/gstack-upgrade`, `/learn`.