Neovim 0.9 clipboard default change and OSC52 opt‑in decision

Answering the Core Question

Neovim 0.9 changed the default value of clipboard to unnamedplus, meaning yanks and pastes use the system clipboard automatically. The OSC52 escape‑sequence method is still opt‑in: you must add clipboard+=osc52 to your configuration. Keeping OSC52 opt‑in preserves the safety boundary that the project introduced in 0.9, but a per‑host whitelist can provide a convenient middle ground for administrators who trust specific SSH hosts.

Recommended Configuration

1. Verify that Neovim was compiled with clipboard support:

   :echo has('clipboard')

   Expect 1. If 0, OSC52 cannot be used.

2. Check the current clipboard setting:

   :set clipboard?

   After a fresh 0.9 install you should see unnamedplus.

3. Enable OSC52 only for trusted hosts. A simple way is to add an autocmd that tests the remote host name and adjusts clipboard accordingly:

" In init.lua or init.vim
if vim.fn.has('clipboard') == 1 then
  local host = os.getenv('HOSTNAME') or ""
  local trusted = {"trusted‑server‑1", "trusted‑server‑2"}
  if vim.tbl_contains(trusted, host) then
    vim.opt.clipboard:append('osc52')
  else
    vim.opt.clipboard:remove('osc52')
  end
end

This keeps the default unnamedplus for local sessions and only adds OSC52 when connecting to a host on the whitelist.

Per‑Host Whitelist Approach

• Pros: Automatic, no manual editing per session.
• Cons: Requires the host name to be reliable and may need adjustment if you use SSH proxies or jump hosts.

If you prefer a more granular approach, you can store the whitelist in a separate file and source it from Neovim:

" ~/.config/nvim/osc52_whitelist.lua
return {"trusted‑server‑1", "trusted‑server‑2"}

" In init.lua
local whitelist = require('osc52_whitelist')
if vim.fn.has('clipboard') == 1 and vim.tbl_contains(whitelist, os.getenv('HOSTNAME')) then
  vim.opt.clipboard:append('osc52')
end

Verification Checklist

• Does :set clipboard? show unnamedplus (or unnamedplus,osc52 when on a trusted host)?
• Can you yank text and see it in the system clipboard when on a trusted host?
• Is osc52 absent when you SSH to an untrusted host?
• Is your terminal emulator capable of OSC52 (e.g., iTerm2, Kitty, Alacritty) and not being wrapped by a multiplexer that blocks the sequence?
• Is has('clipboard') returning 1?

Ask for Missing Diagnostic Detail

To finalize the recommendation, could you confirm whether your terminal emulator supports OSC52 and whether Neovim reports has('clipboard') == 1?