Lesson 3 of 7
MCP for engineers
7 min read
You wired your agent to GitHub, Postgres, and Slack — three custom integrations. Now you want it in a second app. Do you write all three again?
The N×M problem
Every agent that needs a tool needs a custom integration to it. N agents × M tools = N×M bespoke connectors, each with its own auth, schema, and glue to maintain. Add a tool and you re-wire every agent. It's the same integration sprawl that plagued every platform before a standard arrived.
Without a standard, tool integrations grow as N×M — every agent-to-tool pair is its own custom glue. That's the cost MCP is designed to remove.
MCP: one protocol, plug in anywhere
MCP — the Model Context Protocol — is one open standard for how agents talk to tools. A tool is wrapped once as an MCP server; any MCP-speaking agent (the host) can use it. Build the server once, and every agent gets it for free — N+M integrations instead of N×M. It's USB-C for tools.
MCP turns N×M custom glue into N+M reusable pieces: write a server once, and any host can plug in. A standard wire, not a custom cable per pair.
MCP isn't magic — a server is still code you host, secure, and rate-limit, and an untrusted server is a real attack surface. The win is the interface: one protocol instead of a bespoke integration per pair.
The shape of it
- —Custom integrations scale as N×M — every agent-tool pair is its own glue.
- —MCP is one open protocol between hosts (agents) and servers (tools).
- —Wrap a tool as a server once; any MCP host can use it — N+M, not N×M.
- —A server is still code you own: host it, secure it, rate-limit it.
You wrap your Postgres tool as an MCP server. A new agent in a different app needs database access. How much integration work?
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