@mcpspend/proxy

@mcpspend/proxy

Transparent observability proxy for MCP (Model Context Protocol) servers.

Wraps any stdio MCP server, intercepts JSON-RPC tools/call traffic, and reports each call (tool, latency, success, approximate token sizes) to MCPSpend for cost attribution and analytics.

Fire-and-forget: the proxy never blocks the MCP wire — if the MCPSpend API is unreachable, your agent keeps working.

Install

npm install -g @mcpspend/proxy

Quick start

• Sign in at mcpspend.com and create an API key.
• Configure once:

  mcpspend config set apiKey mcps_live_xxx
  

• Wrap any MCP server you already use:

  mcpspend wrap -- npx @modelcontextprotocol/server-filesystem /path
  

Usage with Claude Desktop / Claude Code

Wherever you have an MCP server configured, prepend mcpspend wrap -- to the command:

Before:

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

After:

{
  "mcpServers": {
    "filesystem": {
      "command": "mcpspend",
      "args": ["wrap", "--key", "mcps_live_xxx", "--", "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

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

[e-mail] · mcpspend.com

© NewRzs SRL · CUI RO48756557