TermBuf::Clipboard

Stability: stable — changes only in a major release.

The system clipboard, written through the terminal with OSC 52.

The terminal is the only thing in the picture with a connection to the window system, so a program on the far end of an ssh session sets the clipboard of the machine the human is sitting at rather than the one it is running on. That is the whole appeal, and it is why terminals treat it carefully: many ship with clipboard writes off, and this shard cannot tell a refusal from a success, since nothing is sent back either way.

terminal.clipboard.copy "the selected text"
terminal.clipboard.copy "a middle-click paste", :primary

Everything here is gated on Capability::Osc52Clipboard. Without it #copy writes nothing at all rather than putting a sequence on the wire that a terminal without the feature would print as text.

How much will fit

Nothing here chunks or splits, because there is nothing to chunk into: OSC 52 carries one payload and the limit on it belongs to the terminal, not to the protocol. Kitty defaults to refusing anything over 512KiB, xterm's limit is smaller still and depends on how it was built, and a multiplexer in between adds a limit of its own. A terminal over the limit truncates or drops the write silently, so a caller moving more than a few kilobytes should not expect it to arrive, and cannot find out that it did not.