To me, someone who can code means someone who (unless they're in a detectable state of drunkenness, fatigue, illness, or distraction) will successfully complete a coding task commensurate with some level of experience or, at the very least, explain why exactly the task is proving difficult. While I've seen coding agents do things that truly amaze me, they also make mistakes that no one who "can code" ever makes. If you can't trust an LLM to complete a task anyone who can code will either complete or explain their failure, then it can't code, even if it can (in the sense of "a flipped coin can come up heads") sometimes emit impressive code.