I'm currently working on a small script between tmux and iTerm2 for myself for clipboard integration.

I've worked out that it'd in theory be possible to combine tmux's tmux; passthrough and iTerm2's 1337;CopyToClipboard= escape sequence⁽¹⁾ to do a direct copy from the remote terminal to the local clipboard. I even have a script that somewhat works: https://gist.github.com/cesarkawakami/81a567af45a16522cb7ee20642feed41

The script emits something like this [newlines added for clarity]:

\033Ptmux;\033
\033\033]1337;CopyToClipboard=\007
<whatever>
\033\033]1337;EndCopy\007
\033\\

The problem I'm having is that the passthrough sequence has an upper bound on the number of characters that are passed through. If I'm emitting

\033Ptmux;\033<whatever>\033\\

and <whatever> is larger than (apparently) 211 characters, the command simply doesn't go through.

I've thought about chunking the input, doing something like:

\033Ptmux;\033
\033\033]1337;CopyToClipboard=\007
first_chunk
\033\\
\033Ptmux;\033
second_chunk
\033\033]1337;EndCopy\007
\033\\

But as soon as I emit the first \033\\, tmux emits some escape codes itself, adding spurious characters (from what I can see, they're always \033[1;1H) to the local clipboard.

Is there a way to either (1) avoid emitting these control characters temporariliy or (2) somehow work around the passthrough length limitation?

(1): https://www.iterm2.com/documentation-escape-codes.html