diff --git a/nvim-core/src/lib.rs b/nvim-core/src/lib.rs
index b44d794..56208c3 100644
--- a/nvim-core/src/lib.rs
+++ b/nvim-core/src/lib.rs
@@ -689,7 +689,7 @@ pub async fn run_mcp_loop(app_name: &str, app_version: &str) {
                                 },
                                 {
                                     "name": "nvim_execute_lua",
-                                    "description": "Execute arbitrary Lua code in Neovim and return the result (JSON serialized).",
+                                    "description": "Execute arbitrary Lua code in Neovim and return the result (JSON serialized). CRITICAL: This is the primary tool for editing files. Use `vim.api.nvim_buf_set_lines` to modify buffers. ALWAYS trigger a notification (`require('notify')(...)`). ALWAYS auto-save (`vim.cmd('write')`) after edits. NEVER use interactive commands or 'c' flags in substitutions (e.g. use `vim.cmd('%s/old/new/ge')`).",
                                     "inputSchema": {
                                         "type": "object",
                                         "properties": {