VS Code MCP Client (nys)
A Visual Studio Code extension that connects to Model Context Protocol (MCP) servers. It provides an AI Chat panel, executes prompts, lists available tools, and supports both HTTP/WebSocket servers and local stdio binaries.
Key Features
- Connect to MCP servers
- Standard HTTP/WebSocket servers (default)
- Stdio mode for local binaries (e.g., GitHub MCP server)
- AI Chat webview (View: MCP AI Chat → AI Chat)
- Commands: Connect, Execute Prompt, List Tools, Open Chat View, Disconnect
- Status bar integration (connection/processing state)
- Tool discovery cached on connect (no periodic 30‑min refresh)
- Optional semantic tool selection using external embedding/vector backends (Vector MCP or Milvus)
Requirements
- Visual Studio Code 1.60.0 or newer
- Access to an MCP server:
- Standard HTTP/WebSocket endpoint, or
- A local stdio-compatible binary (e.g., github-mcp-server), or
- Optional demo Filesystem server (run-mcp-server.sh)
- Credentials:
- API key for your MCP/LLM service, or
- GitHub Personal Access Token when using github-mcp-server
- Optional for semantic tool selection:
- Embedding MCP endpoint and Vector MCP endpoint, or
- A reachable Milvus instance
- For building/packaging from source: Node.js and npm
Quick Start
- Install
- From VSIX: Build or download a .vsix, then in VS Code: Extensions → … → Install from VSIX…
- Configure (Settings → “MCP Client”)
- mcpClient.serverUrl
- Standard HTTP/WS example: http://localhost:8080
- Stdio example: /path/to/github-mcp-server (you may pass args; the extension appends "stdio" if missing)
- mcpClient.apiKey or mcpClient.githubToken
- For stdio GitHub MCP server, prefer githubToken. In stdio mode, the extension passes it to GITHUB_PERSONAL_ACCESS_TOKEN/GITHUB_TOKEN.
- mcpClient.modelProvider and mcpClient.modelName (openai | anthropic | gemini)
- Optional semantic settings (see Configuration)
- Use
- Command Palette → MCP: Connect to Server
- Command Palette → MCP: Open Chat View (or MCP: Execute Prompt)
- Command Palette → MCP: List Available Tools
Commands
- MCP: Connect to Server (vscode-mcp-client.connect)
- MCP: Disconnect (vscode-mcp-client.disconnect)
- MCP: Execute Prompt (vscode-mcp-client.executePrompt)
- MCP: List Available Tools (vscode-mcp-client.listTools)
- MCP: Open Chat View (vscode-mcp-client.openChatView)
Configuration (summary)
The extension contributes settings under mcpClient. Common keys:
- serverUrl: string — URL of MCP server, or path to stdio binary
- apiKey: string — API key (LLM/MCP token). In stdio mode for GitHub MCP, githubToken is preferred
- githubToken: string — GitHub Personal Access Token for github-mcp-server
- modelProvider: openai | anthropic | gemini — provider for LLM-assisted parsing/presentation
- modelName: string — model identifier (optional)
Semantic selection (optional, for tool ranking):
- embeddingUrl: string — Embedding MCP endpoint
- vectorUrl: string — Vector MCP endpoint
- namespace: string — Namespace for vectors
- topK: number — Default hits to return
Milvus (optional alternative to Vector MCP):
- milvusAddress: string — Host (e.g., localhost)
- milvusPort: number — Port
- milvusUseSSL: boolean — Use TLS
- milvusUser/milvusPassword: string — Auth (if enabled)
- milvusCollectionPrefix: string — Prefix for collections (default tools_)
Behavior notes:
- Tool catalog is requested and cached on connection; no scheduled refresh. Semantic index rebuilds only when the toolset changes.
Examples
Standard HTTP/WebSocket server (default mode):
{
"mcpClient.serverUrl": "http://localhost:8080",
"mcpClient.apiKey": "YOUR_API_KEY"
}
Stdio GitHub MCP server (binary or Docker):
{
"mcpClient.serverUrl": "/path/to/github-mcp-server",
"mcpClient.githubToken": "YOUR_GITHUB_PAT"
}
Docker example via stdio:
{
"mcpClient.serverUrl": "docker run --rm -i ghcr.io/github/github-mcp-server",
"mcpClient.githubToken": "YOUR_GITHUB_PAT"
}
Packaging (build a VSIX)
Prerequisites: Node.js, npm
npm install
# Standard package (no node_modules included)
npm run package
# Package without dependencies (explicit)
npm run package-no-deps
# Webpack bundle (single-file bundle prior to packaging)
npm run webpack-bundle
# Create a full VSIX including dependencies
npm run create-full-vsix
# One-step install to VS Code (local) if available on your system
npm run direct-install
You can also use scripts/simple-build.sh or bundle-and-install.sh if present in your environment.
Optional: Filesystem Server Helper
A helper script is provided to run a demo Filesystem MCP server in WebSocket mode:
chmod +x ./run-mcp-server.sh
./run-mcp-server.sh --port 8080 --mode websocket --dir /path/to/project
Security & Privacy
- No telemetry is collected by this extension.
- Network access is limited to the endpoints you configure (MCP server, optional Embedding MCP, Vector MCP, or Milvus).
- Credentials:
- Standard HTTP/HTTPS: If provided, an Authorization: Bearer header is used for MCP requests.
- Stdio mode: Tokens are forwarded to the MCP binary via environment variables (GITHUB_PERSONAL_ACCESS_TOKEN, GITHUB_TOKEN, API_KEY) for compatibility.
- Tokens are only persisted if you explicitly save them in VS Code settings.
- Tool discovery is cached in memory for the session after connecting; there is no periodic background refresh.
- Logs may include masked identifiers for debugging; avoid sharing logs that could contain sensitive project details.
Troubleshooting
- Not connected? Ensure serverUrl is correct. For stdio, verify the binary path and that your token is valid.
- GitHub MCP stdio: In stdio mode the extension forwards the token via GITHUB_PERSONAL_ACCESS_TOKEN/GITHUB_TOKEN and API_KEY env vars.
- Tool list empty? Connect first; tools are fetched on connect and cached for the session.
- Semantic selection requires embedding/vector config (Vector MCP) or Milvus connectivity.
Links
License
MIT
