refactor: improve CLI type safety and log level consistency

cli/src/client/connection.ts

@@ -1,16 +1,14 @@
 import { Client } from "@modelcontextprotocol/sdk/client/index.js";
 import type { Transport } from "@modelcontextprotocol/sdk/shared/transport.js";
-import { McpResponse } from "./types.js";
+import type {
+  LoggingLevel,
+  EmptyResult,
+} from "@modelcontextprotocol/sdk/types.js";
+import { LoggingLevelSchema } from "@modelcontextprotocol/sdk/types.js";
 
-export const validLogLevels = [
-  "trace",
-  "debug",
-  "info",
-  "warn",
-  "error",
-] as const;
-
-export type LogLevel = (typeof validLogLevels)[number];
+// Extract valid log levels directly from the SDK's Zod schema to avoid drift
+// This ensures CLI validation stays in sync with what the SDK accepts
+export const validLogLevels = LoggingLevelSchema.options;
 
 export async function connect(
   client: Client,
@@ -38,10 +36,10 @@ export async function disconnect(transport: Transport): Promise<void> {
 // Set logging level
 export async function setLoggingLevel(
   client: Client,
-  level: LogLevel,
-): Promise<McpResponse> {
+  level: LoggingLevel,
+): Promise<EmptyResult> {
   try {
-    const response = await client.setLoggingLevel(level as any);
+    const response = await client.setLoggingLevel(level);
     return response;
   } catch (error) {
     throw new Error(

cli/src/client/prompts.ts

@@ -1,8 +1,11 @@
 import { Client } from "@modelcontextprotocol/sdk/client/index.js";
-import { McpResponse } from "./types.js";
+import {
+  ListPromptsResult,
+  GetPromptResult,
+} from "@modelcontextprotocol/sdk/types.js";
 
 // List available prompts
-export async function listPrompts(client: Client): Promise<McpResponse> {
+export async function listPrompts(client: Client): Promise<ListPromptsResult> {
   try {
     const response = await client.listPrompts();
     return response;
@@ -18,7 +21,7 @@ export async function getPrompt(
   client: Client,
   name: string,
   args?: Record<string, string>,
-): Promise<McpResponse> {
+): Promise<GetPromptResult> {
   try {
     const response = await client.getPrompt({
       name,

cli/src/client/resources.ts

@@ -1,8 +1,14 @@
 import { Client } from "@modelcontextprotocol/sdk/client/index.js";
-import { McpResponse } from "./types.js";
+import {
+  ListResourcesResult,
+  ReadResourceResult,
+  ListResourceTemplatesResult,
+} from "@modelcontextprotocol/sdk/types.js";
 
 // List available resources
-export async function listResources(client: Client): Promise<McpResponse> {
+export async function listResources(
+  client: Client,
+): Promise<ListResourcesResult> {
   try {
     const response = await client.listResources();
     return response;
@@ -17,7 +23,7 @@ export async function listResources(client: Client): Promise<McpResponse> {
 export async function readResource(
   client: Client,
   uri: string,
-): Promise<McpResponse> {
+): Promise<ReadResourceResult> {
   try {
     const response = await client.readResource({ uri });
     return response;
@@ -31,7 +37,7 @@ export async function readResource(
 // List resource templates
 export async function listResourceTemplates(
   client: Client,
-): Promise<McpResponse> {
+): Promise<ListResourceTemplatesResult> {
   try {
     const response = await client.listResourceTemplates();
     return response;

cli/src/client/tools.ts

@@ -1,6 +1,10 @@
 import { Client } from "@modelcontextprotocol/sdk/client/index.js";
-import { Tool } from "@modelcontextprotocol/sdk/types.js";
-import { McpResponse } from "./types.js";
+import {
+  Tool,
+  ListToolsResult,
+  CallToolResult,
+  CompatibilityCallToolResult,
+} from "@modelcontextprotocol/sdk/types.js";
 
 type JsonSchemaType = {
   type: "string" | "number" | "integer" | "boolean" | "array" | "object";
@@ -9,7 +13,7 @@ type JsonSchemaType = {
   items?: JsonSchemaType;
 };
 
-export async function listTools(client: Client): Promise<McpResponse> {
+export async function listTools(client: Client): Promise<ListToolsResult> {
   try {
     const response = await client.listTools();
     return response;
@@ -69,10 +73,10 @@ export async function callTool(
   client: Client,
   name: string,
   args: Record<string, string>,
-): Promise<McpResponse> {
+): Promise<CallToolResult | CompatibilityCallToolResult> {
   try {
     const toolsResponse = await listTools(client);
-    const tools = toolsResponse.tools as Tool[];
+    const tools = toolsResponse.tools;
     const tool = tools.find((t) => t.name === name);
 
     let convertedArgs: Record<string, unknown> = args;

cli/src/client/types.ts

@@ -1 +1,23 @@
-export type McpResponse = Record<string, unknown>;
+import type {
+  ListToolsResult,
+  CallToolResult,
+  CompatibilityCallToolResult,
+  ListPromptsResult,
+  GetPromptResult,
+  ListResourcesResult,
+  ReadResourceResult,
+  ListResourceTemplatesResult,
+  EmptyResult,
+} from "@modelcontextprotocol/sdk/types.js";
+
+// Union type for all possible MCP response types
+export type McpResponse =
+  | ListToolsResult
+  | CallToolResult
+  | CompatibilityCallToolResult
+  | ListPromptsResult
+  | GetPromptResult
+  | ListResourcesResult
+  | ReadResourceResult
+  | ListResourceTemplatesResult
+  | EmptyResult;

cli/src/index.ts

@@ -11,12 +11,12 @@ import {
   listResources,
   listResourceTemplates,
   listTools,
-  LogLevel,
   McpResponse,
   readResource,
   setLoggingLevel,
   validLogLevels,
 } from "./client/index.js";
+import type { LoggingLevel } from "@modelcontextprotocol/sdk/types.js";
 import { handleError } from "./error-handler.js";
 import { createTransport, TransportOptions } from "./transport.js";
 
@@ -26,7 +26,7 @@ type Args = {
   promptName?: string;
   promptArgs?: Record<string, string>;
   uri?: string;
-  logLevel?: LogLevel;
+  logLevel?: LoggingLevel;
   toolName?: string;
   toolArg?: Record<string, string>;
   transport?: "sse" | "stdio" | "http";
@@ -232,13 +232,13 @@ function parseArgs(): Args {
       "--log-level <level>",
       "Logging level (for logging/setLevel method)",
       (value: string) => {
-        if (!validLogLevels.includes(value as any)) {
+        if (!validLogLevels.includes(value as LoggingLevel)) {
           throw new Error(
             `Invalid log level: ${value}. Valid levels are: ${validLogLevels.join(", ")}`,
           );
         }
 
-        return value as LogLevel;
+        return value as LoggingLevel;
       },
     )
     //