MCP Workbench

Discover, validate, and test every MCP server across Cursor, VS Code, and Claude — in one place.

MCP server definitions end up scattered across half a dozen files with different root keys and transport conventions, and a single typo silently drops a server with no warning. MCP Workbench scans every known location, normalizes the results into one tree, and flags the misconfigurations that usually cost you an hour of debugging.

Features

• Unified discovery — one tree of every MCP server found across Cursor, VS Code, Claude Code, and Claude Desktop, grouped by source.
• Transport normalization — stdio, http, and sse servers shown with a consistent shape regardless of which editor's field conventions the file used.
• Configuration validation — surfaces the silent failures: wrong root key, unparseable JSON, npx without -y, and ${ENV} references that aren't set in your environment.
• Connection testing — launch any server over the MCP SDK, run the initialize handshake, and list its capabilities and tools (with input schemas) — or see the exact reason it failed to connect.
• Live tool calls — fire a real tools/call from the panel with arguments pre-filled from each tool's schema, and see the result rendered inline.
• Provenance at a glance — every server shows which file and editor it came from, with the absolute config path one click away.
• Live refresh — re-scans automatically when any known MCP config changes in your workspace.

Screenshots

Hover any server to see its source, the exact config file it came from, and every validation issue:

Where it looks

Source	Location	Root key
Cursor (global)	~/.cursor/mcp.json	mcpServers
Cursor (workspace)	<workspace>/.cursor/mcp.json	mcpServers
VS Code (workspace)	<workspace>/.vscode/mcp.json	servers
Claude Code (workspace)	<workspace>/.mcp.json	mcpServers
Claude Code (user)	~/.claude.json	mcpServers
Claude Desktop	~/.claude/claude_desktop_config.json	mcpServers

Servers recorded per project under projects["<path>"].mcpServers in ~/.claude.json are scoped to the open workspace folder by default. Set mcpWorkbench.showAllClaudeProjects to list every recorded project. Edits to the global config files above refresh the tree automatically.

Validation checks

Issue	Level	What it catches
missing-root-key	error	The right file with the wrong top-level key, so the editor loads no servers without warning.
bad-json	error	A config file that can't be parsed.
unknown-transport	error	An entry with neither a command (stdio) nor a url (http/sse).
empty-root-key	warning	The root key is present but defines no servers.
npx-missing-y	warning	npx without -y/--yes, which can hang waiting for an install prompt.
env-unset	warning	A ${VAR} / ${env:VAR} reference that isn't set in your environment.
non-string-arg / non-string-value	warning	A non-string arg, env value, or header that would otherwise be silently coerced.

Getting started

Run from source

git clone https://github.com/wheelbarrel00/mcpworkbench.git
cd mcpworkbench
npm install
npm run compile

Open the folder in VS Code or Cursor and press F5 to launch an Extension Development Host with MCP Workbench loaded. Click the MCP Workbench icon in the activity bar to open the Servers view.

Install the packaged extension

npx @vscode/vsce package
cursor --install-extension mcp-workbench-wb00-0.2.1.vsix

Then reload Cursor and open the MCP Workbench panel from the activity bar.

Usage

• Refresh — re-scan all locations from the view's title bar.
• Open Config File — right-click a server to jump to the exact file it came from.
• Test Server — click the ▶ button on a server (or right-click → Test Server) to connect over the MCP SDK and open a panel with the server's initialize info, capabilities, and tools — or the exact connection error. The panel stays connected while open: edit a tool's JSON arguments and click Call tool to run it live, then close the panel to disconnect.

Roadmap

• Opt-in support for VS Code user-profile mcp.json paths.

License

MIT