Your app is a restaurant: APIs, MCP, and WebMCP for non-technical builders
This post is basically me resharing my learnings.
I've been deep in APIs, MCP, and WebMCP the last couple weeks. Some of it went semi-viral. A friend helped me see the rest on a call. A sharp reply on the thread filled in a gap I was missing.
Let me explain how I interpret them.
The tourist problem
Here's the thing:
ChatGPT can't actually see your website the way you do.
It hits your page like a tourist who doesn't speak the language. It takes a screenshot. Guesses which button means "checkout." Clicks, waits, screenshots again. Rename a button and the whole thing breaks, because it was never reading your site. It was reverse-engineering it.
I wrote that last week. It took off. Even the OpenAI developer account reshared it. The punchline was WebMCP: stop making agents scrape you like tourists. Tell them what your site can do.
What I didn't fully unpack then: how that fits next to plain APIs and MCP. So here's my mental model.
Your app is a restaurant
I was on a call with a developer friend and we landed on this - same idea as my restaurant / API aha.
The front door is the UI. Built for humans. Menus, tables, a nice experience.
The loading dock out back is the API.
Trucks pull up, drop off, pick up, never touch the dining room.
Same kitchen. Different entrance.
Once you see it that way, the rest falls into place:
- API key = the dock badge. Proves the truck is allowed in and logs who showed up.
- Scopes = which doors the badge opens. Dock yes, walk-in freezer no.
- Rate limits = the dock schedule. You can't back up 40 trucks at once.
- Leaked key = lost badge. Anyone holding it drives in as you.
Most builders obsess over the front door. For Stripe, Twilio, Netlify, most of the business value runs through the dock.
The part people miss
Someone replied with a line that stuck:
Solid analogy. The part people miss: the dock is where break-ins happen too. Nobody picks the front door lock, they clone a badge. Leaked keys and over-scoped tokens still drive most API breaches.
Yes.
That's why rotating your keys isn't paranoia. It's hygiene. Same with tight scopes. Don't hand a truck the walk-in freezer when it only needs the dock.
Never leave a badge in a public repo. Assume anything that shipped in client-side code got photographed.
So where does MCP fit?
If the API is the loading dock, MCP is the shared clipboard every truck driver learns once.
Model Context Protocol is a standard way for AI agents (and tools) to talk to apps. Instead of every agent inventing its own way to knock on every dock, they speak one shape: here are the tools, here are the inputs, here is what comes back.
Same kitchen. Same dock. Now the paperwork is standardized.
That's why MCP feels like magic when it clicks. You're not teaching Cursor (or ChatGPT, or whatever) a brand-new dance for Notion, then Linear, then GitHub. You connect a server. The agent sees named tools. It calls them.
API key still matters. Scopes still matter. Rate limits still matter. Rotate still matters. MCP didn't replace the dock. It made the dock usable by agents without a custom integration every time.
And WebMCP?
Back to the tourist.
WebMCP is when the restaurant itself puts the dock tools in the dining room for agents who already walked in the front door.
Regular MCP: you find a server, connect it, often hand it credentials, then the agent can call tools.
WebMCP: the agent is already on your site, in your signed-in tab. The page registers the real actions next to the UI - searchProducts(), bookFlight(), add_to_cart(). The agent calls those. No screenshots. No guessing. Same difference as scraping a bank's site versus calling its API.
I think of it as the HOV lane.
Screenshot-and-click is the surface streets. WebMCP is the lane that skips the traffic because the site told the agent what it can do.
We spent years making AI better at using websites like humans. Maybe websites just needed to stop pretending the user is always human.
The short version
| Thing | How I interpret it | What it is |
|---|---|---|
| UI | Front door / dining room | Built for humans |
| API | Loading dock | Built for other software |
| API key / scopes / rate limits | Badge, doors, dock schedule | Auth and safety on the dock |
| Key rotation | New badge after a lost one | Best practice because break-ins clone badges |
| MCP | Shared clipboard for truck drivers | Standard tool protocol for agents |
| WebMCP | Dock tools in the live, signed-in tab | Site-native agent actions, no scrape |
Same kitchen the whole time. Different entrances. Different badges. Different lanes.
If you only polish the front door, you're leaving the dock - and the agent HOV lane - on the table. And if you leave a badge taped to the dock wall, you're inviting the wrong truck.
That's my read. Still learning in public.