pastilhasandClaude Opus 5
2a8f0049a3
xterm.js does not handle OSC 52 unless something registers for it, and nothing did. A program offering "press c to copy" emitted the sequence and it vanished, so its confirmation was true about having sent it and false about anything arriving. Found while signing a member into Claude Code on the production host: its first-run login prints an OAuth URL too long to read off a wrapped pane and offers to copy it, "(Copied!)" appeared, and the clipboard was untouched. The URL had to be recovered by running claude under tmux on the server and reassembling it from the captured pane — which is not a thing a member can be asked to do, and first-run login is every new member's first five minutes. Writes only. A lone `?` in the data position is a read request — a program asking the terminal to hand over whatever the user has copied — and it is deliberately not answered: a shell should not be able to exfiltrate the clipboard of the person watching it. The clipboard API needs a secure context and generally a user gesture; the keypress that caused the sequence is that gesture. A refusal is swallowed rather than thrown, since a copy that does not land is the status quo rather than a reason to break the pane. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>