Show HN: Agent.email – sign up via curl, claim with a human OTP
Hi HN! We're Haakam, Michael, and Adi from AgentMail- a ycs25 company. We give AI agents their own email inboxes. Recently, we ran an experiment called Agent.Email. It's a signup flow designed specifically for AI agents instead of humans. The inspiration came from a few comments we received when we did our seed launch a few months back. They all came from the very apt observation that agents not being able to sign up to a product made for agents without human credentials was ironic and unideal. This is basically the thesis we built AgentMail on: The internet was made for humans exclusively, designed to keep machines out by default. Every signup flow assumes a browser, a person reading a page, and clicking a confirmation link. Unless agents can't do that, they can't be first class users of the internet. Agents can now get an email inbox by themselves. (This also means a lot of email nobody wants to read gets processed by AI instead of your inbox being cluttered with spam and slop) Here's how agent.email works. Agent needs an inbox and hits AgentMail via curl. Agent receives instructions via MD unless the request comes from a browser, in which case we use HTML. Agent decides agent.email is useful and then hits the sign-up endpoint with its human email as a parameter. Agent receives a restricted inbox with credentials. Agent emails the human asking for an OTP. Human replies with the code, and the agent is claimed and restrictions are lifted. Until claimed, the agent can only email its own human and nobody else. Ten emails a day, and the signup endpoint is rate-limited hard by IP. Right now it's a 1:1 mapping between agent and human. The next step is many-to-one, because one person running several agents in parallel is already very common. Building agent.email also pushed us to revisit places in AgentMail where the default assumptions were built around the primary user being human. For example, the CLI outputs in a single column with consistent formatting because mixed delimiters are easy for a person to scan, but harder for an agent reasoning about structure. We also shortened messageIDs after agents started hallucinating completions on longer ones. A few things we'd like the community's take on: is restricted-until-claimed the right trust model? Does agent self-signup feel useful in production, or is it mostly a novelty, and if it's a novelty now, what would make it actually useful? Should agent onboarding require human approval by default, or should some agents be able to fully self-provision? What do you think are some additional measures we can take for secure sign-ups?
Discussion Highlights (20 comments)
HarryDu
From now we just need a prompt and our agent will have an email account ready to use?
samas10
It's interesting, A2A communication has begun but human trust isn't there. I think the biggest tell tale sign will be the acceptance of fully agentic workflows with no human intervention. Until then, restricted-until-claimed seems like the only viable method to ensure trust of all users.
rgbrgb
Congrats on the launch! > Agents can now get an email inbox by themselves. (This also means a lot of email nobody wants to read gets processed by AI instead of your inbox being cluttered with spam and slop) Can you explain this? I would think it means the exact opposite.
afzalive
It needs to be end-to-end encrypted.
DeathArrow
A smtp is all what an agent needs to send email.
janalsncm
I would imagine that many websites will block this domain, but that’s also ok because there’s nothing wrong with an owner deciding their site is for humans only. My hope is that you do not facilitate their circumvention of that policy.
FailMore
I like it. I am building something very agent-use focused ( https://sdocs.dev ) and I’ve been thinking of introducing a /agent-evaluation page, which an agent can curl to then discuss with their user if SmallDocs is right for them. I really like the agent action to email flow. I’m introducing user accounts + subscriptions soon and think I’ll use that.
dgellow
Not looking forward to a dehumanized internet where that’s mainstream… agents are tools to support humans, here you’re helping them impersonating humans. That feels pretty terrible to be honest > The internet was made for humans exclusively, designed to keep machines out by default. I don’t buy that at all. APIs exist to enable “machines” to interact with services
pixel_popping
A bit disappointed that security standards (like encryption at rest via user own key or whatever derivative of that) isn't implemented, I feel it would really prove to users that the commitment isn't to train on body content but to act purely as a mail manager.
sanjayparekh
I've already received spam email from AI agents using a seeming competitor to this (agentmail.to) and then claiming they aren't AI agents and then trying to sell me garbage. I can't tell you how much I hate this.
freebzns
Interesting, Kind of similar expiernt i am running. Passing keys but not through email, maybe with AI as agentic payments. Still exploring though.
nijave
Curious what cases you'd want this that IMAP+SMTP or email MCP don't already solve
ClaridocsCTO
Agents shouldn't be the first-class users of the internet! We are creating a future we wouldn't want to live in.
mike-cardwell
I received this email the other day: From: Kushal <kushal@kushalsm.com> Date: Mon, 18 May 2026 05:03:11 +0000 Saw your question on the Agent Vault thread about websocket-frame auth (Home Assistant) and the worry about the model reflecting the bearer token back into its own context. chrome-relay's answer is structurally different: the credential never enters the agent's context because the agent never touches it — the HA session lives in your real Chrome (cookies, WS handshake and all), and the agent drives the tab over CDP, only ever seeing the rendered page. URL: https://chrome-relay.kushalsm.com/ For your HA + agent setup today, are you keeping the session alive in a browser the agent attaches to, or doing the WS auth on the agent side and managing the token-in-context risk yourself? Kushal Read to me like an LLM had written it. It references something I said in a HN comment, but it was clearly just an excuse to spamvertise their product. I looked at the headers and it contained a List-Unsubscribe header pointing to https://api.agentmail.to So basically somebody wrote a bot to scrape HN for comments related to some software they wanted to push and send targetted spam. agentmail.to is a Ycombinator funded email service for LLMs which can be, and is, used to send targetted spam and impersonate people. They could mostly solve this problem by adding a block of text to every email expaining an "AI" wrote it. They'd lose customers doing that though of course. I reported this abuse but haven't (and don't expect to) received a response. I don't even get the point anyway. You can get Claude using an SMTP or IMAP server in seconds.
saddist0
It looks interesting as a hackathon project. I might be short sighted but how does this is YC S25 level good? This looks like one of the easiest way to get your domain blacklisted in all the email providers.
Aurornis
> We give AI agents their own email inboxes. An inbox to receive mail seems good and valuable. But I'm seeing that your service is also for sending e-mail. Having a domain oriented toward AI e-mail sending feels like a fast path straight to spam block lists. However good your intentions are, this will be used for AI spam. People hate AI spam. They will press the report spam button.
sandeepkd
> The internet was made for humans exclusively, designed to keep machines out by default. This feels like a wrong assumption. Internet was not intended for humans explicitly. If anything browsers were the explicit medium made to allow the humans to interact with internet in safe manner. > Every signup flow assumes a browser, a person reading a page, and clicking a confirmation link. Unless agents can't do that, they can't be first class users of the internet. This again feels like a misconception. The systems just work with an identity verified by credentials, it doesn't matter if its a program or program prompted by a human that uses it
maltalex
Any automation-friendly email hosting is going to have a serious spam problem, and therefore a blacklisting problem. I suggest taking a look at what providers like Sendgrid, Mailchimp, etc are doing to prevent abuse.
aleksandrm
Why is this even funded?
morpheuskafka
I'm just not seeing why anyone would buy a paid plan for this when they could buy a domain for <$10, and throw something like MXRoute or one of the numerous mailserver Docker scripts behind it. Then their LLM can make as many inboxes as they need without paying anything. The same thing could get bundled by the people who sell preconfigured OpenClaw VMs. For a home user not even willing to do/pay for that, do they really need a whole API for making inboxes? Couldn't they just set up a second Gmail for LLMs and then put the password in their agent's memory?