diff --git a/nvim-core/src/lib.rs b/nvim-core/src/lib.rs
index f9f458c..3afc596 100644
--- a/nvim-core/src/lib.rs
+++ b/nvim-core/src/lib.rs
@@ -1260,7 +1260,7 @@ pub async fn run_mcp_loop(app_name: &str, app_version: &str) {
                                 handle_lua_result!(id, execute_nvim_lua(code));
                             }
 
-                            "redo" => {
+                            "undo" | "redo" => {
                                 let is_undo = action == "undo";
                                 let steps = args.get("steps").and_then(|v| v.as_i64()).unwrap_or(1);
                                 let cmd = if is_undo {
@@ -1283,6 +1283,37 @@ pub async fn run_mcp_loop(app_name: &str, app_version: &str) {
                                 handle_lua_result!(id, execute_nvim_lua(&code));
                             }
 
+                            "create_scratch" => {
+                                let mut modified_args = args.clone();
+                                if let Some(content) = modified_args.get_mut("content")
+                                    && let Some(s) = content.as_str()
+                                {
+                                    let lines: Vec<String> = s
+                                        .split('\n')
+                                        .map(|l| l.trim_end_matches('\r').to_string())
+                                        .collect();
+                                    *content = serde_json::json!(lines);
+                                }
+                                let args_rmp = json_to_rmpv(&modified_args);
+                                let code = "
+                                    local args = ...
+                                    local name = args.name or 'Scratch'
+                                    local content = args.content or {}
+                                    if type(content) == 'string' then
+                                        content = {content}
+                                    end
+                                    local bufnr = vim.api.nvim_create_buf(true, true)
+                                    pcall(vim.api.nvim_buf_set_name, bufnr, name)
+                                    vim.api.nvim_buf_set_lines(bufnr, 0, -1, false, content)
+                                    vim.api.nvim_win_set_buf(0, bufnr)
+                                    return 'Created and focused scratch buffer: ' .. name
+                                ";
+                                handle_lua_result!(
+                                    id,
+                                    execute_nvim_lua_with_args(code, vec![args_rmp])
+                                )
+                            }
+
                             _ => {
                                 send_error(
                                     id,
@@ -1310,6 +1341,37 @@ pub async fn run_mcp_loop(app_name: &str, app_version: &str) {
                                 ";
                                 handle_lua_result!(id, execute_nvim_lua(lua_code))
                             }
+                            "list_windows" => {
+                                let lua_code = r"
+                                    local wins = vim.api.nvim_list_wins()
+                                    local result = {}
+                                    for _, win in ipairs(wins) do
+                                        if vim.api.nvim_win_is_valid(win) then
+                                            local buf = vim.api.nvim_win_get_buf(win)
+                                            local name = vim.api.nvim_buf_get_name(buf)
+                                            table.insert(result, { id = win, buf_id = buf, buf_name = name })
+                                        end
+                                    end
+                                    return vim.fn.json_encode(result)
+                                ";
+                                handle_lua_result!(id, execute_nvim_lua(lua_code))
+                            }
+                            "focus" => {
+                                if let Some(win_id) = args.get("win_id").and_then(|v| v.as_i64()) {
+                                    let code = format!("
+                                        local win_id = {}
+                                        if vim.api.nvim_win_is_valid(win_id) then
+                                            vim.api.nvim_set_current_win(win_id)
+                                            return 'Focused window ' .. tostring(win_id)
+                                        else
+                                            error('Invalid window ID')
+                                        end
+                                    ", win_id);
+                                    handle_lua_result!(id, execute_nvim_lua(&code));
+                                } else {
+                                    send_error(id, -32602, "Missing 'win_id'").await;
+                                }
+                            }
 
                             "split" => {
                                 let args_rmp = json_to_rmpv(args);
@@ -1537,6 +1599,21 @@ pub async fn run_mcp_loop(app_name: &str, app_version: &str) {
                                     return table.concat(results, "\n\n")
                                 "#
                                 }
+                                "diagnostics" => {
+                                    r#"
+                                    local args = ...
+                                    local bufnr = vim.fn.bufnr(args.file)
+                                    if bufnr == -1 then return "Buffer not found" end
+                                    local diags = vim.diagnostic.get(bufnr)
+                                    if #diags == 0 then return "No diagnostics found" end
+                                    local results = {}
+                                    for _, d in ipairs(diags) do
+                                        local severity = vim.diagnostic.severity[d.severity] or "UNKNOWN"
+                                        table.insert(results, string.format("[%s] Line %d: %s", severity, d.lnum + 1, d.message))
+                                    end
+                                    return table.concat(results, "\n")
+                                "#
+                                }
 
                                 _ => "",
                             };
@@ -1584,9 +1661,9 @@ pub async fn run_mcp_loop(app_name: &str, app_version: &str) {
                                     send_error(id, -32602, "Missing 'line' or 'text'").await;
                                 }
                             }
-                            "clear" => {
+                            "highlight" | "clear" => {
                                 let mut modified_args = args.clone();
-                                if action == "clear_highlight"
+                                if action == "clear"
                                     && let Some(obj) = modified_args.as_object_mut()
                                 {
                                     obj.insert("clear_only".to_string(), json!(true));