Codex Hooks Library

Save as .codex/hooks/block-dangerous-bash.sh, make it executable, and register it under before_tool_use in your Codex configuration.

#!/usr/bin/env bash
INPUT="$(cat)"
COMMAND="$(echo "$INPUT" | jq -r '.tool_input.command // ""')"

if echo "$COMMAND" | grep -Eiq '(rm\s+-rf\s+(/|~|\$HOME)|sudo\s|git\s+push\s+.*--force|curl[^|]*\|\s*(ba)?sh|wget[^|]*\|\s*(ba)?sh|DROP\s+(TABLE|DATABASE)|TRUNCATE\s+TABLE|mkfs|dd\s+if=.*of=/dev/)'; then
  jq -n --arg msg "Blocked destructive command: $COMMAND. Explain what you are trying to do and propose a safer alternative." \
    '{ "decision": "deny", "reason": $msg }'
  exit 0
fi

jq -n '{ "decision": "allow" }'

Save as .codex/hooks/block-package-installs.sh, make it executable, and register it under before_tool_use in your Codex configuration.

#!/usr/bin/env bash
INPUT="$(cat)"
COMMAND="$(echo "$INPUT" | jq -r '.tool_input.command // ""')"

if echo "$COMMAND" | grep -Eiq '(npm install|npm i |pnpm add|yarn add|bun add|pip install|uv add|composer require|cargo add|go get)'; then
  jq -n --arg msg "Package install blocked for review: $COMMAND. Do not install packages automatically. Explain why the dependency is needed and ask for approval." \
    '{ "decision": "deny", "reason": $msg }'
  exit 0
fi

jq -n '{ "decision": "allow" }'

Save as .codex/hooks/protect-env-files.sh, make it executable, and register it under before_tool_use in your Codex configuration.

#!/usr/bin/env bash
INPUT="$(cat)"
FILE_PATH="$(echo "$INPUT" | jq -r '.tool_input.file_path // ""')"

if echo "$FILE_PATH" | grep -Eiq '(^|/)(\.env|\.env\.|secrets?/|credentials|\.pem$|\.key$|id_rsa)'; then
  jq -n --arg msg "Blocked write to protected path: $FILE_PATH. Secrets and environment files are managed manually. Ask the user instead." \
    '{ "decision": "deny", "reason": $msg }'
  exit 0
fi

jq -n '{ "decision": "allow" }'

Save as .codex/hooks/prevent-secrets-in-code.sh, make it executable, and register it under before_tool_use in your Codex configuration.

#!/usr/bin/env bash
INPUT="$(cat)"
CONTENT="$(echo "$INPUT" | jq -r '.tool_input.content // .tool_input.new_string // ""')"

if echo "$CONTENT" | grep -Eq '(sk-[A-Za-z0-9]{20,}|AKIA[0-9A-Z]{16}|ghp_[A-Za-z0-9]{30,}|xox[baprs]-[A-Za-z0-9-]{10,}|eyJ[A-Za-z0-9_-]{20,}\.[A-Za-z0-9_-]{20,}\.[A-Za-z0-9_-]{20,})'; then
  jq -n --arg msg "Possible hardcoded secret detected in the edit. Block the write, show the offending line, and propose moving the value to an environment variable." \
    '{ "decision": "deny", "reason": $msg }'
  exit 0
fi

jq -n '{ "decision": "allow" }'

Save as .codex/hooks/block-commit-to-main.sh, make it executable, and register it under before_tool_use in your Codex configuration.

#!/usr/bin/env bash
INPUT="$(cat)"
COMMAND="$(echo "$INPUT" | jq -r '.tool_input.command // ""')"

if echo "$COMMAND" | grep -Eq '(git\s+(commit|push)).*(main|master)|git\s+push\s+(origin\s+)?(main|master)(\s|$)'; then
  jq -n --arg msg "Direct commits/pushes to main are blocked. Create a feature branch, commit there, and open a pull request." \
    '{ "decision": "deny", "reason": $msg }'
  exit 0
fi

jq -n '{ "decision": "allow" }'

Save as .codex/hooks/typecheck-after-edit.sh, make it executable, and register it under after_tool_use in your Codex configuration.

#!/usr/bin/env bash
INPUT="$(cat)"
FILE_PATH="$(echo "$INPUT" | jq -r '.tool_input.file_path // ""')"

# Only care about TypeScript files
echo "$FILE_PATH" | grep -Eq '\.(ts|tsx)$' || { echo '{}'; exit 0; }

# Only run when the project has a typecheck script
[ -f package.json ] && jq -e '.scripts["typecheck"]' package.json >/dev/null 2>&1 || { echo '{}'; exit 0; }

if ! npm run typecheck >/tmp/codex-typecheck.log 2>&1; then
  REASON="Typecheck failed after editing $FILE_PATH. Fix the errors before continuing:\n$(tail -n 20 /tmp/codex-typecheck.log)"
  jq -n --arg msg "$REASON" '{ "decision": "block", "reason": $msg }'
  exit 0
fi

jq -n '{}'

Save as .codex/hooks/lint-after-edit.sh, make it executable, and register it under after_tool_use in your Codex configuration.

#!/usr/bin/env bash
INPUT="$(cat)"
FILE_PATH="$(echo "$INPUT" | jq -r '.tool_input.file_path // ""')"

echo "$FILE_PATH" | grep -Eq '\.(js|jsx|ts|tsx)$' || { echo '{}'; exit 0; }

[ -f package.json ] && jq -e '.scripts["lint"]' package.json >/dev/null 2>&1 || { echo '{}'; exit 0; }

if ! npm run lint >/tmp/codex-lint.log 2>&1; then
  REASON="Lint failed after editing $FILE_PATH. Fix the reported issues before continuing:\n$(tail -n 20 /tmp/codex-lint.log)"
  jq -n --arg msg "$REASON" '{ "decision": "block", "reason": $msg }'
  exit 0
fi

jq -n '{}'

Save as .codex/hooks/log-diffs-after-edit.sh, make it executable, and register it under after_tool_use in your Codex configuration.

#!/usr/bin/env bash
INPUT="$(cat)"
FILE_PATH="$(echo "$INPUT" | jq -r '.tool_input.file_path // ""')"
LOG_DIR="${CODEX_PROJECT_DIR:-.}/.codex/friction-log"

if [ -n "$FILE_PATH" ]; then
  mkdir -p "$LOG_DIR"
  {
    echo "--- $(date +%FT%T) $FILE_PATH"
    git diff -- "$FILE_PATH" 2>/dev/null | head -n 40
  } >> "$LOG_DIR/$(date +%F).log"
fi

jq -n '{}'