(CAT-2609) Add safety hooks for Claude Code

.claude/hooks/_parse_input.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+# Shared helper: reads hook JSON from stdin and sets $cmd to the Bash tool command.
+# Sources into each hook with: . "$(dirname "$0")/_parse_input.sh"
+# Exits 0 (allow) if no JSON parser is available.
+
+if command -v jq >/dev/null 2>&1; then
+  # shellcheck disable=SC2034  # cmd is used by the sourcing hook script
+  cmd=$(jq -r '.tool_input.command // ""' 2>/dev/null || echo "")
+elif command -v python3 >/dev/null 2>&1; then
+  # shellcheck disable=SC2034  # cmd is used by the sourcing hook script
+  cmd=$(python3 -c "import sys,json; print(json.load(sys.stdin).get('tool_input',{}).get('command',''))" 2>/dev/null || echo "")
+else
+  exit 0
+fi

.claude/hooks/no-main-commits.sh

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+# Project rule: never work directly on the main or master branch.
+# Blocks: git commit when current branch is main or master.
+
+# shellcheck source=/dev/null
+. "$(dirname "$0")/_parse_input.sh"
+
+if echo "$cmd" | grep -qE '(^|[;&|`(])[[:space:]]*(([[:alpha:]_][[:alnum:]_]*=[^[:space:]]*[[:space:]]+)*)([^[:space:]]*/)?git[[:space:]]+commit([[:space:]]|$|[;&|])'; then
+  branch=$(git rev-parse --abbrev-ref HEAD 2>/dev/null)
+  if [ "$branch" = "main" ] || [ "$branch" = "master" ]; then
+    echo "{\"continue\":false,\"stopReason\":\"Project rule: never work directly on the $branch branch.\"}"
+  fi
+fi

.claude/hooks/no-pr-merge.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# Project rule: never merge a pull request.
+# Blocks: gh pr merge
+
+# shellcheck source=/dev/null
+. "$(dirname "$0")/_parse_input.sh"
+
+if echo "$cmd" | grep -qE '(^|[;&|])[[:space:]]*gh pr merge'; then
+  echo '{"continue":false,"stopReason":"Project rule: never merge a pull request."}'
+fi

.claude/hooks/no-push.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# Project rule: never push a branch without explicit instruction.
+# Blocks: git push
+
+# shellcheck source=/dev/null
+. "$(dirname "$0")/_parse_input.sh"
+
+if echo "$cmd" | grep -qE '(^|[;&|`(])[[:space:]]*(([[:alpha:]_][[:alnum:]_]*=[^[:space:]]*[[:space:]]+)*)([^[:space:]]*/)?git[[:space:]]+push([[:space:]]|$|[;&|])'; then
+  echo '{"continue":false,"stopReason":"Project rule: never push a branch without explicit instruction."}'
+fi

.claude/hooks/no-rm.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+# Project rule: never delete a file without explicit permission.
+# Blocks: rm, sudo rm, xargs rm, /bin/rm, /usr/bin/rm (and similar absolute paths).
+# Does not cover: find -exec rm (rm as a subprocess argument, not a shell token).
+
+# shellcheck source=/dev/null
+. "$(dirname "$0")/_parse_input.sh"
+
+if echo "$cmd" | grep -qE '(^|[;&|])[[:space:]]*(sudo[[:space:]]+|xargs[[:space:]]+)?([^[:space:]]*/)?rm([[:space:]]|$)'; then
+  echo '{"continue":false,"stopReason":"Project rule: never delete a file without explicit permission."}'
+fi

.claude/settings.json

@@ -0,0 +1,32 @@
+{
+  "hooks": {
+    "PreToolUse": [
+      {
+        "matcher": "Bash",
+        "hooks": [
+          {
+            "type": "command",
+            "command": ".claude/hooks/no-pr-merge.sh",
+            "timeout": 5,
+            "statusMessage": "Checking project rules..."
+          },
+          {
+            "type": "command",
+            "command": ".claude/hooks/no-main-commits.sh",
+            "timeout": 5
+          },
+          {
+            "type": "command",
+            "command": ".claude/hooks/no-push.sh",
+            "timeout": 5
+          },
+          {
+            "type": "command",
+            "command": ".claude/hooks/no-rm.sh",
+            "timeout": 5
+          }
+        ]
+      }
+    ]
+  }
+}

CLAUDE.md

@@ -96,6 +96,8 @@ If you change template behavior, update:
 
 ## Project Rules
 
+- At the start of a coding session, review the repository structure and any relevant README or documentation files to understand the area you are working in.
+- Always read the files relevant to the task before suggesting or making a change.
 - Never merge a pull request.
 - Never work directly on the `main` or `master` branch.
 - Never push a branch without explicit instruction.