OSC 52 Clipboard Setup

Overview

OSC 52 is an escape sequence that allows remote terminals to write to the local system clipboard over SSH. This enables yanking in Neovim on the devbox and pasting locally on macOS.

How It's Configured in This Repo

tmux (assets/tmux/extra.conf)

set -s set-clipboard on              # Accept OSC 52 from apps
set -gq allow-passthrough on         # tmux 3.3+ passthrough support
set -as terminal-features ',xterm-256color:clipboard'  # Ms capability

Neovim (assets/nvim/lua/user/settings.lua)

-- HOW to talk to clipboard (use OSC 52 escape sequences)
vim.g.clipboard = "osc52"

-- WHEN to use clipboard (sync unnamed register with +)
vim.opt.clipboard = "unnamedplus"

Both are required: vim.g.clipboard sets the provider, vim.opt.clipboard makes yanks use it by default.

Local Terminal (iTerm2)

Preferences → General → Selection → Enable "Applications in terminal may access clipboard"

Testing

Test 1: Raw SSH (no tmux)

ssh devbox
printf '\033]52;c;%s\007' "$(printf 'test-raw' | base64 | tr -d '\n')"
# Cmd+V locally should paste "test-raw"

Test 2: Inside tmux

ssh devbox
tmux new
printf '\033]52;c;%s\007' "$(printf 'test-tmux' | base64 | tr -d '\n')"
# Cmd+V locally should paste "test-tmux"

Test 3: Inside Neovim

nvim somefile
# Yank a line with `yy`
# Cmd+V locally should paste the line

Test 4: Verify nvim settings

:lua print(vim.g.clipboard)
" Should print: osc52

:lua print(vim.o.clipboard)
" Should print: unnamedplus

Troubleshooting

If Tests 1 & 2 pass but Test 3 fails (nvim yanks don't reach clipboard):

Check that vim.opt.clipboard = "unnamedplus" is set. Without this, yanks go to the unnamed register, not the + register that OSC 52 uses.

:lua print(vim.o.clipboard)
" Should print: unnamedplus

If Test 2 fails (tmux), check:

tmux show -s set-clipboard    # Should be: on
tmux info | grep 'Ms:'        # Should NOT say [missing]

After changing tmux config: Must restart tmux server, not just detach/attach:

tmux kill-server

Local Terminal Support

Note on Paste

OSC 52 is primarily for copy (yank → local clipboard). Pasting from local clipboard into remote nvim typically uses your terminal's paste function (Cmd+V in insert mode, or terminal's paste bracketing).

Images

OSC 52 only handles text. For sharing images with Claude Code over SSH, use the screenshot-to-devbox helper script, which:

1. Takes a screenshot on macOS
2. Uploads it to the devbox via scp
3. Copies the remote path to clipboard

Then paste the path into Claude Code:

Analyze this image: /home/dev/.cache/claude-images/screenshot-20240115-143022-12345.png