AI agents like Claude Code can write and run code, but they still hit the same walls as traditional automation: interactive prompts, flaky APIs, GUI-only software, and stateless restarts. These 9 Python libraries — pexpect, watchfiles, plumbum, fire, tenacity, streamz, diskcache, pywinauto, and boltons — handle those edge cases. An agent that knows when to use them builds more robust automation than one that brute-forces everything with subprocess and while loops.