Large Language Models (LLM) & AI Market: Stop Claude Code agent writing outside directory

The article explains two complementary guardrails for preventing unattended Claude Code agents from writing files outside an intended directory: declarative permission rules in settings.json (permissions.deny) and a programmatic PreToolUse hook that inspects pending tool calls and can deny writes. It details how deny/allow precedence makes an allow-list impossible with permissions.deny alone, shows a Node.js hook implementation that defers on malformed payloads and denies out-of-scope writes, and warns that hooks cannot see writes from Bash commands, subagents, or generated build artefacts. As a post-hoc check, the author recommends running a git-status diff against an allow-list before committing to catch any changes the hook missed. The piece clarifies these measures are not an OS sandbox and outlines trade-offs such as failing-open behavior.