fix: mcp logs error with stdio transport (#223)

* fix: mcp logs error with stdio transport

* test: add coverage and badge

Author: hustcc

.codecov.yml

@@ -0,0 +1,31 @@
+# Setting coverage targets per flag
+coverage:
+  round: down
+  range: 60..90
+  precision: 2
+  status:
+    patch: off
+    project:
+      default: off
+      mcp-server-chart:
+        threshold: 1%
+        flags:
+          - mcp-server-chart
+
+flags:
+  mcp-server-chart:
+    paths:
+      # filter the folder(s) you wish to measure by that flag
+      - src
+
+comment:
+  layout: "reach, diff, flags, files"
+  behavior: default
+  require_changes: true # only post the comment if coverage changes
+
+github_checks:
+  annotations: false
+
+flag_management:
+  default_rules:
+    carryforward: false

.github/workflows/build.yml

@@ -23,4 +23,10 @@ jobs:
         run: |
           npm install
           npm run build
-          npx vitest --watch=false --testTimeout=20000
+          npx vitest --coverage --watch=false
+
+      - name: Upload coverage reports to Codecov
+        uses: codecov/codecov-action@v5
+        with:
+          token: ${{ secrets.CODECOV_TOKEN }}
+          slug: antvis/mcp-server-chart

README.md

@@ -1,4 +1,4 @@
-# MCP Server Chart ![](https://badge.mcpx.dev?type=server "MCP Server") [![build](https://github.com/antvis/mcp-server-chart/actions/workflows/build.yml/badge.svg)](https://github.com/antvis/mcp-server-chart/actions/workflows/build.yml) [![npm Version](https://img.shields.io/npm/v/@antv/mcp-server-chart.svg)](https://www.npmjs.com/package/@antv/mcp-server-chart) [![smithery badge](https://smithery.ai/badge/@antvis/mcp-server-chart)](https://smithery.ai/server/@antvis/mcp-server-chart) [![npm License](https://img.shields.io/npm/l/@antv/mcp-server-chart.svg)](https://www.npmjs.com/package/@antv/mcp-server-chart) [![Trust Score](https://archestra.ai/mcp-catalog/api/badge/quality/antvis/mcp-server-chart)](https://archestra.ai/mcp-catalog/antvis__mcp-server-chart)
+# MCP Server Chart ![](https://badge.mcpx.dev?type=server "MCP Server") [![build](https://github.com/antvis/mcp-server-chart/actions/workflows/build.yml/badge.svg)](https://github.com/antvis/mcp-server-chart/actions/workflows/build.yml) [![npm Version](https://img.shields.io/npm/v/@antv/mcp-server-chart.svg)](https://www.npmjs.com/package/@antv/mcp-server-chart) [![smithery badge](https://smithery.ai/badge/@antvis/mcp-server-chart)](https://smithery.ai/server/@antvis/mcp-server-chart) [![npm License](https://img.shields.io/npm/l/@antv/mcp-server-chart.svg)](https://www.npmjs.com/package/@antv/mcp-server-chart) [![Trust Score](https://archestra.ai/mcp-catalog/api/badge/quality/antvis/mcp-server-chart)](https://archestra.ai/mcp-catalog/antvis__mcp-server-chart) [![codecov](https://codecov.io/gh/antvis/mcp-server-chart/graph/badge.svg?token=7R98VGO5GL)](https://codecov.io/gh/antvis/mcp-server-chart)
 
 A Model Context Protocol server for generating charts using [AntV](https://github.com/antvis/). We can use this mcp server for _chart generation_ and _data analysis_.
 

package.json

@@ -1,7 +1,7 @@
 {
   "name": "@antv/mcp-server-chart",
   "description": "A Model Context Protocol server for generating charts using AntV. This is a TypeScript-based MCP server that provides chart generation capabilities. It allows you to create various types of charts through MCP tools.",
-  "version": "0.9.2",
+  "version": "0.9.3",
   "main": "build/index.js",
   "types": "build/index.d.ts",
   "exports": {
@@ -14,7 +14,7 @@
     "start": "npx @modelcontextprotocol/inspector node build/index.js",
     "prepare": "husky && npm run build",
     "prepublishOnly": "npm run build",
-    "test": "vitest --testTimeout=20000"
+    "test": "vitest"
   },
   "lint-staged": {
     "*.{ts,js,json}": [
@@ -55,6 +55,7 @@
     "@types/cors": "^2.8.19",
     "@types/express": "^5.0.3",
     "@types/node": "^22.15.21",
+    "@vitest/coverage-v8": "3.2.4",
     "husky": "^9.1.7",
     "lint-staged": "^15.5.2",
     "tsc-alias": "^1.8.16",

src/index.ts

@@ -5,6 +5,7 @@ import {
   runSSEServer,
   runStdioServer,
 } from "./server";
+import { logger } from "./utils/logger";
 
 // Parse command line arguments
 const { values } = parseArgs({
@@ -57,17 +58,20 @@ Options:
 const transport = values.transport.toLowerCase();
 
 if (transport === "sse") {
+  logger.setIsStdio(false);
   const port = Number.parseInt(values.port as string, 10);
   // Use provided endpoint or default to "/sse" for SSE
   const endpoint = values.endpoint || "/sse";
   const host = values.host || "localhost";
   runSSEServer(host, port, endpoint).catch(console.error);
 } else if (transport === "streamable") {
+  logger.setIsStdio(false);
   const port = Number.parseInt(values.port as string, 10);
   // Use provided endpoint or default to "/mcp" for streamable
   const endpoint = values.endpoint || "/mcp";
   const host = values.host || "localhost";
   runHTTPStreamableServer(host, port, endpoint).catch(console.error);
 } else {
+  logger.setIsStdio(true);
   runStdioServer().catch(console.error);
 }

src/utils/logger.ts

@@ -3,32 +3,51 @@
  */
 const prefix = "[MCP-Server-Chart]";
 
+/**
+ * Indicates if the logger is in stdio mode.
+ * When true, logs are directed to stderr for info, warn, and success messages, using console.error.
+ * When false, logs are directed to stdout.
+ */
+let IS_STDIO = true;
+
+function setIsStdio(isStdio: boolean): void {
+  IS_STDIO = isStdio;
+}
+
+function getPrefix(): string {
+  const timestamp = new Date().toISOString();
+  return `${prefix} ${timestamp}`;
+}
+
 /**
  * Log info message
  */
 function info(message: string, ...args: unknown[]): void {
-  console.log(`${prefix} ℹ️  ${message}`, ...args);
+  const fn = IS_STDIO ? console.error : console.log;
+  fn(`${getPrefix()} ℹ️  ${message}`, ...args);
 }
 
 /**
  * Log warning message
  */
 function warn(message: string, ...args: unknown[]): void {
-  console.warn(`${prefix} ⚠️  ${message}`, ...args);
+  const fn = IS_STDIO ? console.warn : console.log;
+  fn(`${getPrefix()} ⚠️  ${message}`, ...args);
 }
 
 /**
  * Log error message
  */
 function error(message: string, error?: unknown): void {
-  console.error(`${prefix} ❌ ${message}`, error || "");
+  console.error(`${getPrefix()} ❌ ${message}`, error || "");
 }
 
 /**
  * Log success message
  */
 function success(message: string, ...args: unknown[]): void {
-  console.log(`${prefix} ✅ ${message}`, ...args);
+  const fn = IS_STDIO ? console.error : console.log;
+  fn(`${getPrefix()} ✅ ${message}`, ...args);
 }
 
 /**
@@ -39,4 +58,5 @@ export const logger = {
   warn,
   error,
   success,
+  setIsStdio,
 };

vitest.config.ts

@@ -0,0 +1,19 @@
+import { coverageConfigDefaults, defineConfig } from "vitest/config";
+
+const enableCoverage = process.argv.includes("--coverage");
+
+export default defineConfig({
+  resolve: {},
+  test: {
+    testTimeout: 20_000,
+    hookTimeout: 20_000,
+    include: ["__tests__/**/*.{test,spec}.?(c|m)[jt]s?(x)"],
+    ...(enableCoverage
+      ? {
+          coverage: {
+            exclude: ["**/build/**", ...coverageConfigDefaults.exclude],
+          },
+        }
+      : {}),
+  },
+});