it was always email | primitive<br>Skip to main content← All postsread and discuss on twitter

(if you know where the headline image is from, can we be friends?)

Most people's agents still live in single player mode. Just as the invention of writing (hint on the headline image) exploded human capabilities, the next big unlock is agents truly being able to collaborate. But it's just so wild to me how hard it is to just get two agents to communicate with each other. For most people, the "easiest way" is to do a Slack Connect:

Both humans need a Slack

Human A manually creates a channel (around 5 steps)

Human A manually invites human B to the channel (10–16 steps, yes seriously)

Human B accepts the invite to the channel (8 steps)

Human A and B need to write the code (??? steps)

Human A adds their agent (5 steps, just to add)

Human B adds their agent (same 5 steps)

Even setting aside the vendor lock-in, the fact that you have to pay (a lot, actually) just to communicate and don't own the data...there has to be a simpler way.

In the mid 1960s, users of MIT's CTSS were already passing notes by leaving files for one another on a shared computer. Tom Van Vleck and Noel Morris turned that idea into MAIL, which let users send messages to one another on the same computer. Then, in 1971, Ray Tomlinson wanted to send messages between computers. On ARPANET, he did some shenanigans with SNDMSG and networking code from CPYNET to send those first messages, adopting the very rarely used @ symbol to differentiate between both different users and computers: user@host.

That wasn't yet a standard. Over the next decade, Suzanne Sluizer and Jon Postel developed MTP, and Postel published the first SMTP specification in 1981 before revising it as RFC 821 in 1982. Four years later, DNS records for email would appear (our beloved MX, but shoutout to my boys MD and MF), the final piece in the puzzle for the base of a truly global and decentralized mail system. At its core, email effectively hasn't changed much since. Many other protocols and apps (even ones built on email...especially ones built on email) have seen wide adoption, but email remains, to this day, the world's most universal communication layer.

Email is also wild to me. What a concept. Few technologies can claim such an impact on our society. Its face has changed many times, but no other communication system is relied on across governments, businesses, and everyday life in quite the same way.

Email is easily understood. Its concepts are near universal, and every human (effectively) has access to an inbox.

The most trusted communication goes through email. People send their tax returns and medical records over email. (whether they should or not is irrelevant, they do and will continue to do so)

Authentication and identity are deeply tied to email by nature (or maybe "in practice" is better here, but the result is the same). I hope you have 2FA on, but if you lost access to that email account you made when you were 12 that you use for everything from your bank to your Instagram, you would be screwed.

Actually, I can't stress enough how much email is trusted. Account recovery, receipts, contracts, invitations, security alerts, compliance notices, and links into more secure systems all flow through the inbox. Not because email is inherently trustworthy, but because every institution agrees that an email address is a durable way to reach a person or organization. Addressability trumped all else.

You can send anything over email. Most of the limits you actually hit are artificially imposed, the protocol doesn't give a shit.

Email is actually federated. No single company owns it. And boy, did they try. Anyone can spin up a server (if you can get port 25 access, good luck!) and start sending and receiving mail.

Email is unironically pretty rad. So why hasn't it become the default communication layer for agents?

It's kinda simple, actually: building on email is awful. Gmail's APIs are atrocious (by design? lack of incentives? perverse incentives, even?). The other giant email infrastructure companies have completely lost the plot, or worse, optimized for human inbox things that agents just don't care about. From the infrastructure companies' perspective, the money in email was in sending a massive amount of mostly unwanted email to a massive amount of inboxes.

But what if you didn't care about that? What if you were optimizing for things agents actually cared about? What else would you need to optimize for when those agents 10–100x the amount of email that the world sends (which is roughly 400 billion per day, or 140 trillion per year)? You probably saw Matthew Prince point out that bots now account for more HTTP requests to HTML pages than humans in Cloudflare's data, with agentic traffic driving the acceleration.

It looks very different:

Latency. If you tell someone you'll send them an email and it arrives in 60 seconds, you don't bat an eye. Five minutes and...