avante.lua

local M = {}
local State = require("mcphub.state")

function M.mcp_tool()
    return {
        name = "mcp",
        description = "The Model Context Protocol (MCP) enables communication with locally running MCP servers that provide additional tools and resources to extend your capabilities. This tool calls mcp tools and resources on the mcp servers using `use_mcp_tool` and `access_mcp_resource` actions respectively.",
        param = {
            type = "table",
            fields = {
                {
                    name = "action",
                    description = "Action to perform: one of `access_mcp_resource` or `use_mcp_tool`. Must be provided always.",
                    type = "string",
                },
                {
                    name = "server_name",
                    description = "Name of the MCP server. Must be provided always.",
                    type = "string",
                },
                {
                    name = "uri",
                    description = "URI of the resource or resourceTemplate to access when using `access_mcp_resource` action",
                    type = "string",
                },
                {
                    name = "tool_name",
                    description = "Name of the tool to call while using `use_mcp_tool` action",
                    type = "string",
                },
                {
                    name = "arguments",
                    description = "Arguments for the `use_mcp_tool` action. Must be an object",
                    type = "object",
                },
            },
        },
        returns = {
            {
                name = "result",
                description = "Result from the MCP tool",
                type = "string",
            },
            {
                name = "error",
                description = "Error message if the call failed",
                type = "string",
                optional = true,
            },
        },
        func = function(params, on_log, on_complete)
            local hub = require("mcphub").get_hub_instance()
            if not hub then
                return nil, "MCP Hub not initialized"
            end

            if not params.server_name then
                return nil, "server_name is required"
            end
            if vim.tbl_contains({ "access_mcp_resource", "use_mcp_tool" }, params.action) == false then
                return nil, "action must be one of `access_mcp_resource` or `use_mcp_tool`"
            end
            if params.action == "access_mcp_resource" and not params.uri then
                return nil, "uri is required"
            end

            if params.action == "use_mcp_tool" and not params.tool_name then
                params.arguments = params.arguments or {}
                if type(params.arguments) ~= "table" then
                    return nil, "arguments must be an object"
                end
                return nil, "tool_name is required"
            end
            local auto_approve = vim.g.mcphub_auto_approve == true
            if not auto_approve then
                local utils = require("mcphub.extensions.utils")
                local confirmed = utils.show_mcp_tool_prompt({
                    action = params.action,
                    server_name = params.server_name,
                    tool_name = params.tool_name,
                    uri = params.uri,
                    arguments = params.arguments,
                })

                if not confirmed then
                    return nil, "User cancelled the operation"
                end
            end
            local sidebar = require("avante").get()
            if params.action == "access_mcp_resource" then
                hub:access_resource(params.server_name, params.uri, {
                    parse_response = true,
                    caller = {
                        type = "avante",
                        avante = sidebar,
                    },
                    callback = function(result, err)
                        --result has .text and .images [{mimeType, data}]
                        on_complete(result.text, err)
                    end,
                })
            elseif params.action == "use_mcp_tool" then
                hub:call_tool(params.server_name, params.tool_name, params.arguments, {
                    parse_response = true,
                    caller = {
                        type = "avante",
                        avante = sidebar,
                    },
                    callback = function(result, err)
                        on_complete(result.text, err)
                    end,
                })
            else
                return nil, "Invalid action type"
            end
        end,
    }
end

return M