The Model Context Protocol is everywhere right now. Every agent tutorial opens with "first, set up your MCP servers." And yet the agent stack running on the machine I'm typing this from — search monitoring, Telegram alerting, social posting, a voice assistant — contains exactly zero MCP servers. Everything talks to external services through direct API calls.

That's not a rejection of MCP. It's a protocol, not a movement — and the flood of agent-architecture content keeps turning plumbing decisions into identity decisions. You're not an "MCP shop" or "behind." You're making a per-workload integration choice, and it comes down to two gates: one decides whether MCP is even the relevant category, the other decides whether it's worth the overhead.

Gate one — relevance: does a model pick the tool at runtime?

MCP exists to solve a specific problem: a language model, mid-session, deciding which tool to use. The protocol standardises how a model discovers tools, what their schemas look like, and how results come back. That's its entire reason to exist — it's a model-facing protocol. If no model is ever choosing, MCP isn't the relevant category; you'd share a library or stand up a plain service.