HarkBot

Hark is a consumer AI assistant from Hark Labs, the company founded by Brett Adcock. Its Handoff agent runs a cloud computer with real browsers that sign in to sites and finish web tasks for the user, such as paying bills, cancelling subscriptions, shopping and topping up cards. Hark previewed Handoff on Aug 5, 2026 and made Hark Pro free on web, iOS and Android on Oct 6, 2026, with Handoff as its cloud computer and paid tiers at $20 and $100 a month for more usage.

Adoption arrived fast. Hark reported 130,208 Handoff browser sessions and 143,244 daily active users in the first 24 hours after the free launch, figures the company shared publicly and that have not been independently checked. Verisoul does not have enough named HarkBot traffic yet to report volumes.

Hark also stands out for a better reason: it is one of the few consumer agents that publishes all three identity signals a site owner can check.

How Hark shows up on your site

Each Handoff request gets a dedicated virtual computer with its own browser, file system and terminal, and the model drives it with cursor and keyboard actions. Handoff can run up to six browsers at once, users can watch a live view, and credentials sit in a vault Hark calls Secured by Hark. Hark's terms say it normally asks for confirmation before spending money or sending messages.

Hark's bot documentation describes HarkBot as a user-initiated fetcher that sends HarkBot/1.0, signs with Web Bot Auth using an Ed25519 key published at hark.com/.well-known/http-message-signatures-directory, and comes from IP ranges listed at hark.com/agent/ipranges/harkbot.json. Hark says to refetch that file rather than pin it. Cloudflare Radar lists HarkBot as a verified bot with that signature directory, so sites behind Cloudflare can allow or block it by name. What the docs don't say is whether full interactive Handoff browser sessions send the same identity.

Why Hark is easy to detect

When an agent publishes a user agent, a signing key and an IP list, a site can verify it end to end: match the token, check the signature against the key directory and confirm the source IP, which gives you proof instead of a guess. Hark also says fetches are user-initiated only, with no crawling or prefetching, so the traffic is tied to a person's request.

The one open question is coverage. Hark documents this identity for its fetch tool, and it is unconfirmed whether every interactive Handoff session carries it. An unsigned Handoff session would look like ordinary Chrome from Hark's cloud, so look at your own logs before treating the signature as complete.

How Verisoul detects Hark

Verisoul verifies the Web Bot Auth signature against Hark's published key, which is the cryptographic signal, and then checks that the browser is cloud hosted with a virtual machine device profile and that clicks, typing and page flow are automated. A valid signature names the operator, and the device and behavior checks confirm the session is what it claims.

"agent": {
  "id": "harkbot",
  "name": "HarkBot",
  "provider": "Hark",
  "type": "ai_agent",
  "detection_method": "signed",
  "detection_signals": [
    "cryptographic",
    "behavioral"
  ]
}

• id is harkbot, the name for Hark's agent in your rules
• type is ai_agent, an agent working in its own browser
• detection_method is signed, meaning a verified signature identified Hark
• detection_signals lists cryptographic, device and behavioral

See the Agent Atlas entry for HarkBot for the sample response, and the AI agent detection docs for how signed detection works.

How to detect Hark step by step

1. Turn on Verisoul on login, billing, checkout and cancellation pages so each session returns an agent field
2. Filter for agent.id equal to harkbot with detection_method set to signed
3. Allow verified harkbot sessions on everyday tasks and score any unnamed Hark-like automation by bot score, per the AI agent detection docs
4. Send HarkBot sign-ups, payouts and payment method changes to review

Should you block Hark?

HarkBot works for real users paying bills, shopping and cancelling subscriptions, so most teams allow verified sessions. Blocking a bill payment or a cancellation made by a customer's own agent tends to create support tickets rather than prevent fraud.

Add review on sign-up, payouts and payment method changes. Hark's free tier means anyone can run Handoff, so the steps where a new account or a new card earns money are the ones worth checking.