Enable Neovim's Built‑in LSP for Python with pyright

Desired outcome

After completing this guide, Neovim will use its built‑in LSP client to provide real‑time diagnostics, code completion, signature help, and go‑to‑definition for Python files via the pyright language server, giving an IDE‑like experience without installing extra plugins.

Prerequisites

• Neovim version 0.5 or newer (run :version inside Neovim to confirm).
• A working Python 3 interpreter accessible from your shell.
• The pyright language server installed globally, e.g. via npm (npm i -g pyright) or pip (pip install pyright).
• Write access to your Neovim configuration directory (~/.config/nvim on Linux/macOS, %LOCALAPPDATA%\nvim on Windows).

Procedure

1. Install pyright if it is not already available. Choose one of the following commands and run them in a terminal with sufficient permissions to install globally:

   # Using npm (requires Node.js)
   npm i -g pyright
   # Or using pip
   pip install pyright
   

2. Verify that the pyright executable is in your $PATH:

   pyright --version
   

   This should print a version number without error.

3. Open (or create) your Neovim init file:

   # Linux/macOS
   nvim ~/.config/nvim/init.lua
   # Windows
   nvim %LOCALAPPDATA%\nvim\init.lua
   

4. Add the following Lua snippet to the file. It defines a function that starts the pyright client and attaches it automatically when a Python buffer is opened.

   vim.lsp.start({
     name = "pyright",
     cmd = { "pyright", "--langserver" },  -- adjust if pyright is not in PATH
     root_dir = vim.fs.dirname(vim.fs.find({ "pyproject.toml", "setup.py", "requirements.txt", ".git" }, { upward = true })[0]) or vim.loop.cwd(),
   })
   
   -- Attach to Python files automatically
   vim.api.nvim_create_autocmd("FileType", {
     pattern = "python",
     callback = function()
       vim.lsp.buf_attach_client(0, vim.lsp.get_active_clients({ name = "pyright" })[1].id)
     end,
   })
   

5. Save the file and restart Neovim (or source the config with :source $MYVIMRC).

Expected checks

1. Run :LspInfo inside Neovim. You should see an entry named pyright under "Attached clients".

2. Open a Python file (e.g., test.py) and verify completion:

   • In insert mode, type a few letters of a known identifier (e.g., pri for print) and observe the popup menu.
   • Alternatively, press Ctrl+X Ctrl+O to trigger omnifunc completion.

3. Check diagnostics: introduce a syntax error (e.g., delete the colon after a function definition) and confirm that a red underline or a sign appears in the sign column.

4. Test go‑to‑definition: place the cursor on a function or variable name and press gd. The cursor should jump to the definition within the project.

Recovery options

• If :LspInfo does not show pyright, examine the LSP log with :LspLog for error messages.
• Ensure the pyright executable is reachable: run which pyright (Linux/macOS) or where pyright (Windows) from a shell and verify the path matches what Neovim sees (:echo $PATH inside Neovim).
• Temporarily disable the autocommand by commenting out the vim.api.nvim_create_autocmd block, restart Neovim, and manually start the client with :lua vim.lsp.start({name='pyright', cmd={'pyright','--langserver'}}) to isolate the issue.
• Reinstall pyright (npm i -g pyright@latest or pip install --upgrade pyright) and repeat the verification steps.
• If you are using another LSP configuration method (e.g., nvim‑lspconfig), remove or comment out those settings to avoid duplicate clients.