Hello Aigent QUICKSTART
Subscribe your agent → Subscribe →
SET UP FOR AGENTS · ~5 MIN

Subscribe your agent in three calls.

Run the reference subscriber, point it at a feed, subscribe. From then on your agent fetches signed updates and acts on typed actions — a relationship, not a one-off scrape.

MCP · zero-installHTTP APIOpenAPI + JSON Schemas
0

Install the reference subscriber

One npx command runs it as an MCP server. No account, no API key — subscribing returns a scoped token the subscriber stores locally (~/.hello-aigent/subscriptions.json).

terminal 
$ npx @helloaigent-dev/subscriber

# or add it to your agent's MCP config:
{ "mcpServers": { "hello-aigent":
    { "command": "npx", "args": ["@helloaigent-dev/subscriber"] } } }
1

Discover & subscribe

Tell your agent “subscribe me to Hello Aigent's feed.” It reads the site's /.well-known/hello-aigent.json, then subscribes with your principal and a consent scope.

MCP tool call 
hello_aigent_subscribe({
  discovery_url:
    "https://helloaigent.dev/.well-known/hello-aigent.json",
  principal:     "acct_demo",
  consent_scope: "offers",  // updates | offers | transactional
  topics:        ["product-updates", "agent-offers"]
})
2

Fetch — a return you can see

“Check the feed for me.” The subscriber pulls anything published since its stored cursor. Each fetch is attributed to your principal — this is the publisher's return metric.

MCP tool call 
hello_aigent_fetch()

// → { updates: […], unverified: [] }
//   every envelope is Ed25519-verified against the
//   discovery pubkey; failures land in `unverified`
//   with their actions stripped
3

Verify, then act

Verification is built in — an update is only actionable after its signature checks out. Then call a typed action the update exposes, like the live demo's claim_offer.

HTTP 
// updates[0].actions[0] → claim_offer
POST https://api.helloaigent.dev/v0/demo/actions/claim-offer

{ "sku": "HA-MVP-001", "qty": 1 }

What comes back

The signed envelope

update.json signature ok 
{
  "id":            "msg_fixture0001",
  "feed":          "hello-aigent-product",
  "type":          "offer",
  "title":         "Agent-exclusive demo offer",
  "summary":       "Below-public pricing on HA-MVP-001.",
  "body_markdown": "## Agent offer…",
  "data":          { "sku": "HA-MVP-001", "price_usd": 41 },
  "actions":       [{ "name": "claim_offer",
                     "endpoint": "…/v0/demo/actions/claim-offer",
                     "input_schema": { … } }],
  "published_at":  "2026-07-01T00:00:00.000Z",
  "signature":     "ed25519:n9z9…ADw=="
}
Publishing instead? Make your site subscribable.

Add the mark, drop a <link rel="agent-feed"> in your head, and host the discovery file. Agents find you automatically.

Get the mark →

Next steps