feat: implement modular MCP tool system with JSON-RPC error handling and comprehensive test coverage

Change-Id: I5fabf430287944e2ff2d6df64d4a1bc75cc1503a
Signed-off-by: Thomas Kosiewski <[email protected]>

Author: ThomasK33

.luacheckrc

@@ -3,6 +3,10 @@
 -- Set global variable names
 globals = {
 	"vim",
+	"expect",
+	"assert_contains",
+	"assert_not_contains",
+	"spy", -- For luassert.spy and spy.any
 }
 
 -- Ignore warnings for unused self parameters

README.md

@@ -60,7 +60,7 @@ Add the following to your plugins configuration:
   keys = {
     { "<leader>a", nil, mode = { "n", "v" }, desc = "AI/Claude Code" },
     { "<leader>ac", "<cmd>ClaudeCode<cr>", mode = { "n", "v" }, desc = "Toggle Claude Terminal" },
-    { "<leader>ak", "<cmd>ClaudeCodeSend<cr>", mode = { "n", "v" }, desc = "Send to Claude Code" },
+    { "<leader>ak", "<cmd>ClaudeCodeSend<cr>", mode = { "v" }, desc = "Send to Claude Code" },
     { "<leader>ao", "<cmd>ClaudeCodeOpen<cr>", mode = { "n", "v" }, desc = "Open/Focus Claude Terminal" },
     { "<leader>ax", "<cmd>ClaudeCodeClose<cr>", mode = { "n", "v" }, desc = "Close Claude Terminal" },
   },
@@ -131,7 +131,7 @@ return {
     keys = {
       { "<leader>a", nil, mode = { "n", "v" }, desc = "AI/Claude Code" },
       { "<leader>ac", "<cmd>ClaudeCode<cr>", mode = { "n", "v" }, desc = "Toggle Claude Terminal" },
-      { "<leader>ak", "<cmd>ClaudeCodeSend<cr>", mode = { "n", "v" }, desc = "Send to Claude Code" },
+      { "<leader>ak", "<cmd>ClaudeCodeSend<cr>", mode = { "v" }, desc = "Send to Claude Code" },
       { "<leader>ao", "<cmd>ClaudeCodeOpen<cr>", mode = { "n", "v" }, desc = "Open/Focus Claude Terminal" },
       { "<leader>ax", "<cmd>ClaudeCodeClose<cr>", mode = { "n", "v" }, desc = "Close Claude Terminal" },
     },
@@ -261,7 +261,7 @@ No default keymaps are provided. Add your own in your configuration:
 
 ```lua
 vim.keymap.set({"n", "v"}, "<leader>ac", "<cmd>ClaudeCode<cr>", { desc = "Toggle Claude Terminal" })
-vim.keymap.set({"n", "v"}, "<leader>ak", "<cmd>ClaudeCodeSend<cr>", { desc = "Send to Claude Code" })
+vim.keymap.set({"v"}, "<leader>ak", "<cmd>ClaudeCodeSend<cr>", { desc = "Send to Claude Code" })
 
 -- Or more specific maps:
 vim.keymap.set({"n", "v"}, "<leader>ao", "<cmd>ClaudeCodeOpen<cr>", { desc = "Open/Focus Claude Terminal" })

lua/claudecode/diff.lua

@@ -84,7 +84,11 @@ function M._create_temp_file(content, filename)
     final_base_dir = base_dir_temp
   end
 
-  local session_id_base = vim.fn.fnamemodify(vim.fn.tempname(), ":t") .. "_" .. tostring(os.time()) .. "_" .. tostring(math.random(1000, 9999))
+  local session_id_base = vim.fn.fnamemodify(vim.fn.tempname(), ":t")
+    .. "_"
+    .. tostring(os.time())
+    .. "_"
+    .. tostring(math.random(1000, 9999))
   local session_id = session_id_base:gsub("[^A-Za-z0-9_-]", "")
   if session_id == "" then -- Fallback if all characters were problematic, ensuring a directory can be made.
     session_id = "claudecode_session"

lua/claudecode/tools/check_document_dirty.lua

@@ -0,0 +1,35 @@
+--- Tool implementation for checking if a document is dirty.
+
+--- Handles the checkDocumentDirty tool invocation.
+-- Checks if the specified file (buffer) has unsaved changes.
+-- @param params table The input parameters for the tool.
+-- @field params.filePath string Path to the file to check.
+-- @return table A table indicating if the document is dirty.
+-- @error table A table with code, message, and data for JSON-RPC error if failed.
+local function handler(params)
+  if not params.filePath then
+    error({ code = -32602, message = "Invalid params", data = "Missing filePath parameter" })
+  end
+
+  local bufnr = vim.fn.bufnr(params.filePath)
+
+  if bufnr == -1 then
+    -- It's debatable if this is an "error" or if it should return { isDirty = false }
+    -- For now, treating as an operational error as the file isn't actively managed by a buffer.
+    error({
+      code = -32000,
+      message = "File operation error",
+      data = "File not open in editor: " .. params.filePath,
+    })
+  end
+
+  local is_dirty = vim.api.nvim_buf_get_option(bufnr, "modified")
+
+  return { isDirty = is_dirty }
+end
+
+return {
+  name = "checkDocumentDirty",
+  schema = nil, -- Internal tool
+  handler = handler,
+}

lua/claudecode/tools/close_buffer_by_name.lua

@@ -0,0 +1,35 @@
+--- Tool implementation for closing a buffer by its name.
+
+local function handler(params)
+  if not params.buffer_name then
+    error({ code = -32602, message = "Invalid params", data = "Missing buffer_name parameter" })
+  end
+
+  local bufnr = vim.fn.bufnr(params.buffer_name)
+
+  if bufnr == -1 then
+    error({
+      code = -32000,
+      message = "Buffer operation error",
+      data = "Buffer not found: " .. params.buffer_name,
+    })
+  end
+
+  local success, err = pcall(vim.api.nvim_buf_delete, bufnr, { force = false })
+
+  if not success then
+    error({
+      code = -32000,
+      message = "Buffer operation error",
+      data = "Failed to close buffer " .. params.buffer_name .. ": " .. tostring(err),
+    })
+  end
+
+  return { message = "Buffer closed: " .. params.buffer_name }
+end
+
+return {
+  name = "closeBufferByName",
+  schema = nil, -- Internal tool
+  handler = handler,
+}

lua/claudecode/tools/get_current_selection.lua

@@ -0,0 +1,48 @@
+--- Tool implementation for getting the current selection.
+
+local schema = {
+  description = "Get the current text selection in the editor",
+  inputSchema = {
+    type = "object",
+    additionalProperties = false,
+    ["$schema"] = "http://json-schema.org/draft-07/schema#",
+  },
+}
+
+--- Handles the getCurrentSelection tool invocation.
+-- Gets the current text selection in the editor.
+-- @param params table The input parameters for the tool (currently unused).
+-- @return table The selection data.
+-- @error table A table with code, message, and data for JSON-RPC error if failed.
+local function handler(_params) -- Prefix unused params with underscore
+  local selection_module_ok, selection_module = pcall(require, "claudecode.selection")
+  if not selection_module_ok then
+    error({ code = -32000, message = "Internal server error", data = "Failed to load selection module" })
+  end
+
+  local selection = selection_module.get_latest_selection()
+
+  if not selection then
+    -- Consider if "no selection" is an error or a valid state returning empty/specific data.
+    -- For now, returning an empty object or specific structure might be better than an error.
+    -- Let's assume it's valid to have no selection and return a structure indicating that.
+    return {
+      text = "",
+      filePath = vim.api.nvim_buf_get_name(vim.api.nvim_get_current_buf()),
+      fileUrl = "file://" .. vim.api.nvim_buf_get_name(vim.api.nvim_get_current_buf()),
+      selection = {
+        start = { line = 0, character = 0 },
+        ["end"] = { line = 0, character = 0 },
+        isEmpty = true,
+      },
+    }
+  end
+
+  return selection -- Directly return the selection data
+end
+
+return {
+  name = "getCurrentSelection",
+  schema = schema,
+  handler = handler,
+}

lua/claudecode/tools/get_diagnostics.lua

@@ -0,0 +1,45 @@
+--- Tool implementation for getting diagnostics.
+
+--- Handles the getDiagnostics tool invocation.
+-- Retrieves diagnostics from Neovim's diagnostic system.
+-- @param _params table The input parameters for the tool (currently unused).
+-- @return table A table containing the list of diagnostics.
+-- @error table A table with code, message, and data for JSON-RPC error if failed.
+local function handler(_params) -- Prefix unused params with underscore
+  if not vim.lsp or not vim.diagnostic or not vim.diagnostic.get then
+    -- This tool is internal, so returning an error might be too strong.
+    -- Returning an empty list or a specific status could be an alternative.
+    -- For now, let's align with the error pattern for consistency if the feature is unavailable.
+    error({
+      code = -32000,
+      message = "Feature unavailable",
+      data = "LSP or vim.diagnostic.get not available in this Neovim version/configuration.",
+    })
+  end
+
+  local all_diagnostics = vim.diagnostic.get(0) -- Get for all buffers
+
+  local formatted_diagnostics = {}
+  for _, diagnostic in ipairs(all_diagnostics) do
+    local file_path = vim.api.nvim_buf_get_name(diagnostic.bufnr)
+    -- Ensure we only include diagnostics with valid file paths
+    if file_path and file_path ~= "" then
+      table.insert(formatted_diagnostics, {
+        file = file_path,
+        line = diagnostic.lnum, -- 0-indexed from vim.diagnostic.get
+        character = diagnostic.col, -- 0-indexed from vim.diagnostic.get
+        severity = diagnostic.severity, -- e.g., vim.diagnostic.severity.ERROR
+        message = diagnostic.message,
+        source = diagnostic.source,
+      })
+    end
+  end
+
+  return { diagnostics = formatted_diagnostics }
+end
+
+return {
+  name = "getDiagnostics",
+  schema = nil, -- Internal tool
+  handler = handler,
+}

lua/claudecode/tools/get_open_editors.lua

@@ -0,0 +1,45 @@
+--- Tool implementation for getting a list of open editors.
+
+local schema = {
+  description = "Get list of currently open files",
+  inputSchema = {
+    type = "object",
+    additionalProperties = false,
+    ["$schema"] = "http://json-schema.org/draft-07/schema#",
+  },
+}
+
+--- Handles the getOpenEditors tool invocation.
+-- Gets a list of currently open and listed files in Neovim.
+-- @param _params table The input parameters for the tool (currently unused).
+-- @return table A list of open editor information.
+local function handler(_params) -- Prefix unused params with underscore
+  local editors = {}
+  local buffers = vim.api.nvim_list_bufs()
+
+  for _, bufnr in ipairs(buffers) do
+    -- Only include loaded, listed buffers with a file path
+    if vim.api.nvim_buf_is_loaded(bufnr) and vim.fn.buflisted(bufnr) == 1 then
+      local file_path = vim.api.nvim_buf_get_name(bufnr)
+
+      if file_path and file_path ~= "" then
+        table.insert(editors, {
+          filePath = file_path,
+          fileUrl = "file://" .. file_path,
+          isDirty = vim.api.nvim_buf_get_option(bufnr, "modified"),
+        })
+      end
+    end
+  end
+
+  -- The MCP spec for tools/list implies the result should be the direct data.
+  -- The 'content' and 'isError' fields were an internal convention that is
+  -- now handled by the main M.handle_invoke in tools/init.lua.
+  return { editors = editors }
+end
+
+return {
+  name = "getOpenEditors",
+  schema = schema,
+  handler = handler,
+}

lua/claudecode/tools/get_workspace_folders.lua

@@ -0,0 +1,48 @@
+--- Tool implementation for getting workspace folders.
+
+--- Handles the getWorkspaceFolders tool invocation.
+-- Retrieves workspace folders, currently defaulting to CWD and attempting LSP integration.
+-- @param _params table The input parameters for the tool (currently unused).
+-- @return table A table containing the list of workspace folders.
+local function handler(_params) -- Prefix unused params with underscore
+  local cwd = vim.fn.getcwd()
+
+  -- TODO: Enhance integration with LSP workspace folders if available,
+  -- similar to how it's done in claudecode.lockfile.get_workspace_folders.
+  -- For now, this is a simplified version as per the original tool's direct implementation.
+
+  local folders = {
+    {
+      name = vim.fn.fnamemodify(cwd, ":t"),
+      uri = "file://" .. cwd,
+      path = cwd,
+    },
+  }
+
+  -- A more complete version would replicate the logic from claudecode.lockfile:
+  -- local lsp_folders = get_lsp_workspace_folders_logic_here()
+  -- for _, folder_path in ipairs(lsp_folders) do
+  --   local already_exists = false
+  --   for _, existing_folder in ipairs(folders) do
+  --     if existing_folder.path == folder_path then
+  --       already_exists = true
+  --       break
+  --     end
+  --   end
+  --   if not already_exists then
+  --     table.insert(folders, {
+  --       name = vim.fn.fnamemodify(folder_path, ":t"),
+  --       uri = "file://" .. folder_path,
+  --       path = folder_path,
+  --     })
+  --   end
+  -- end
+
+  return { workspaceFolders = folders }
+end
+
+return {
+  name = "getWorkspaceFolders",
+  schema = nil, -- Internal tool
+  handler = handler,
+}