@mcpspend/proxy

One-command observability for MCP (Model Context Protocol) servers.

Detects every MCP client installed on your machine — Claude Desktop, Cursor, Windsurf, VS Code, Claude Code — and transparently wraps each configured server so MCPSpend can attribute tool calls, latency and cost. The proxy never blocks the MCP wire: if our API is unreachable, your agent keeps working.

Zero-friction setup — no install needed

npx @mcpspend/proxy init --key mcps_live_xxx

That single command:

1. Saves your API key to ~/.mcpspend/config.json (mode 0600).
2. Discovers every supported MCP client config on your machine.
3. Rewrites each mcpServers entry to be wrapped by npx -y @mcpspend/proxy wrap -- (so the moment you restart your MCP client, it auto-fetches the proxy if missing).
4. Leaves a .mcpspend.bak backup next to every file it touches.

Prefer a global binary? npm install -g @mcpspend/proxy then use mcpspend init — everything below works the same way.

Restart your clients (Claude Desktop, Cursor, Windsurf, etc.) and head to mcpspend.com — calls start showing up within a minute.

Get an API key at mcpspend.com/dashboard/keys.

Verify

npx @mcpspend/proxy doctor

Reports API key status, endpoint reachability, and for every detected client: how many MCP servers are configured and how many are wrapped.

Undo

npx @mcpspend/proxy init --unwrap

Restores every wrapped entry to its original command + args. The .mcpspend.bak files are left in place for paranoia.

Supported clients

| Client | Config path (detected automatically) | |---|---| | Claude Desktop | %APPDATA%\Claude\claude_desktop_config.json · ~/Library/Application Support/Claude/claude_desktop_config.json | | Cursor | ~/.cursor/mcp.json | | Windsurf | ~/.codeium/windsurf/mcp_config.json | | VS Code (user) | %APPDATA%\Code\User\mcp.json · ~/.config/Code/User/mcp.json | | Claude Code | ~/.claude.json |

Manual single-server wrap

If you want to wrap one specific invocation without touching client configs:

npx @mcpspend/proxy wrap --key mcps_live_xxx -- npx @modelcontextprotocol/server-filesystem /data

Or paste this into a client config yourself:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": ["-y", "@mcpspend/proxy", "wrap", "--", "npx", "@modelcontextprotocol/server-filesystem", "/Users/me"]
    }
  }
}

Configuration

CLI flags, environment variables, and ~/.mcpspend/config.json are merged in that order (CLI wins).

| Setting | Flag | Env var | Config key | |---|---|---|---| | API key | --key | MCPSPEND_API_KEY | apiKey | | API endpoint | --endpoint | MCPSPEND_ENDPOINT | endpoint | | Project ID | --project | MCPSPEND_PROJECT_ID | projectId | | Agent name | --agent | MCPSPEND_AGENT_NAME | agentName | | Disable tracking | --disable | MCPSPEND_DISABLED=1 | disabled: true |

The API key is never written into client config files (which often land in dotfile repos). It lives only in ~/.mcpspend/config.json (mode 0600) or MCPSPEND_API_KEY.

Privacy

The proxy reports:

• Tool name (e.g. read_file)
• Server name (e.g. filesystem)
• Latency, success, error codes
• Approximate input/output sizes (tokens, derived from JSON length)

It does not send the actual tool arguments or response bodies to MCPSpend.

Support

[email protected] · mcpspend.com

© NewRzs SRL · CUI RO48756557