Connecting Codex CLI, Cursor, and Antigravity via MCP

I’ve spent this series building an orchestration system almost nobody else could see: a worker model, a supervisor, a retry loop, a Slack approval gate, all wired into one LangGraph process I run from my own terminal. Useful, but lonely. Only my orchestrator ever called any of it.

Today that changes. I turn the system into something other tools can plug into: Codex CLI, Cursor, and Google’s Antigravity IDE, all talking to the same tool hub through the Model Context Protocol (MCP). MCP is an open protocol that lets any AI client discover and call tools exposed by a server, without a bespoke integration for each pairing. If you’ve been following along, you already have the orchestrator — this post is about wiring more clients into it, not rebuilding it.

MCP Hub Architecture: Centralising Tool Access for Multiple AI Clients

Instead of teaching every tool its own Slack logic, its own file-writing logic, its own retry logic, I centralise all of that behind one MCP server:

                ┌───────────────────────┐
                │     Codex CLI         │
                ├───────────────────────┤
                │       Cursor          │
                ├───────────────────────┤
                │     Antigravity       │
                └────────────▲──────────┘
                             │
                             │ MCP
                             │
                     ┌───────┴────────┐
                     │  MCP Tool Hub  │
                     │ (your tools)   │
                     └───────▲────────┘
                             │
                             │ tool boundary
                             │
                     ┌───────┴────────┐
                     │ LangGraph Core │
                     │ Orchestrator   │
                     └────────────────┘

The MCP hub exposes a small set of tools — write a file, request Slack approval, log an event — and anything that speaks MCP can call them. The orchestrator remains the brain. The MCP server becomes the one stable interface everything else talks to.