Introduction

mcpgw is a single binary that keeps one list of your MCP servers, pushes that list into every client that wants its own copy, and — when you ask it to — stands in the middle of the traffic so you can see what your agents are actually calling.

Two problems, one binary

The first is bookkeeping. Claude Desktop keeps its server list in one file. Claude Code keeps its own. Cursor spells the same entry differently. VS Code has a fourth shape. One server, four files, four schemas — and every token rotation means finding all four again.

mcpgw makes ~/.config/mcpgw/config.toml the canonical list and syncs it outward. It only ever rewrites entries it wrote itself; anything you added by hand is left alone and reported back to you as unmanaged. Every client file is backed up before it's touched, and one command puts the previous version back.

The second is visibility. Once the servers are wired up, you have no idea what's happening through them. Which tool did the agent pick? What arguments went out? Did that call fail, or did the server quietly return nothing?

Run mcpgw serve and every client talks to one endpoint instead of to each server directly. The gateway writes every request to a daily JSONL file, and mcpgw watch follows it live:

$ mcpgw watch
watching /Users/you/.local/share/mcpgw/traffic (Ctrl-C to stop)
  now  ✓  github__create_issue               87ms
  12s  ✓  linear tools/list                   4ms
  30s  ✗  github__search_code               210ms  upstream "github" failed after 3 attempt(s)

Why not the MCP Inspector

The official MCP Inspector connects to a server as its own client, so everything it shows you is traffic Inspector generated. That's the right tool for poking at a server you're writing. It is the wrong tool for the question "what did my agent just do".

mcpgw sits on the path the agent already uses, so the log is the agent's own calls.

Where it sits

agentgateway targets Kubernetes and enterprise deployments. MetaMCP gives you aggregation and a web UI, in exchange for a Node and Docker stack you have to keep alive. mcpgw is a static binary with no runtime dependencies doing the boring local job: one config, every client, real traffic.

Start with Installation, then run mcpgw with no arguments — on a terminal that opens the setup wizard, which walks the Quickstart for you one confirmed step at a time.