nvim-install

Install Neovim in the web sandbox

This is the missing half of the neovim RPC skill: that skill drives a running Neovim via $NVIM, but the sandbox ships neither the binary nor a parent editor. This skill installs Neovim, launches it headless on a listen socket, and exports $NVIM so the neovim skill's commands work verbatim afterwards.

Scope: web sandbox only (CLAUDE_CODE_REMOTE=true). Do not run on a real machine — there Neovim is managed by bob at ~/.local/share/bob/nvim-bin/nvim.

Why Nix, not bob

Nix installs Neovim from *.nixos.org (allow-listed by default), so the binary needs no GitHub access — and nixpkgs-unstable ships a current Neovim with vim.pack, which nvim-fredrik requires. bob is available too (see the end), but bob install downloads Neovim as a GitHub release asset, which the GitHub proxy blocks unless neovim/neovim is attached to the session — regardless of network level. So Nix is the default; bob is an opt-in.

Step 0 — Network prerequisites

Two independent mechanisms gate traffic; they bite at different points.

1. The binary (this skill): substituted from the Nix cache (*.nixos.org), reachable under the default Trusted network policy. No GitHub, no action. Verify:

   curl -sSI -o /dev/null -w "cache:    %{http_code}\n" https://cache.nixos.org
   curl -sSI -o /dev/null -w "channels: %{http_code}\n" https://channels.nixos.org/nixpkgs-unstable/nixexprs.tar.xz
   

2. The plugins (a full nvim-fredrik run): at startup vim.pack clones ~50 plugins. These split three ways:

   • Public GitHub clones — already work under the default Trusted policy (github.com is allow-listed). No action.
   • codeberg.org plugins (nvim-lint, nvim-dap, nvim-dap-python) — required and blocked by default. Edit the environment → Network access selector → Custom → in Allowed domains add the bare codeberg.org → tick "Also include default list of common package managers" → save. This rebuilds the environment. See https://code.claude.com/docs/en/claude-code-on-the-web. Gotcha: use the apex codeberg.org, not *.codeberg.org — the wildcard matches only subdomains, but the plugin src URLs are https://codeberg.org/..., so a *.codeberg.org-only allowlist still 403s the clones. (Full network access also works but is broader than needed.)
   • GitHub release assets (codediff's prebuilt lib, Mason LSP servers, treesitter parsers) — gated by the GitHub proxy to attached repos regardless of network level, so they may 403. Optional for observing most config behavior; attach a specific repo with add_repo only if the change under test needs it.