Simon Willison’s Weblog
Comment My comment on MCP was always a bad idea? — Hacker News
This article entirely misses the value that MCP brings today.
Sure, there's almost no reason to use MCPs if you are running a full-blown terminal agent (Claude Code, Codex, Meta Muse, OpenClaw etc) with unfettered internet access - just let it call APIs directly.
If you want to operate something that's less YOLO than that, you'll find yourself wanting:
Control over exactly which external services it can access
A way to handle authentication that doesn't allow the agent to directly access API keys
A sensible UI to allow users to connect and authenticate further services
Strong audit logging for what's going on
MCP makes all of that so much easier to provide.
Thinking MCP is obsolete because full coding agents don't need it misses out on all of the other things we might want to build.
Recent articles
Generating running routes with GPT-6 Astra and ChatGPT Work - 12th September 2026
OpenAI agents attacked RubyGems back in May - 12th September 2026
Some thoughts on the Navier–Stokes Millennium Prize Problem - 8th September 2026
This is a beat by Simon Willison, posted on 20th September 2026 .
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