The permission layer for voice agents
Don't trust the voice. Trust the permission.
A voice agent can only propose an action. Halyn decides — allow, step-up, hold or deny — from policy, proof and signals, and only Halyn can execute it.
Aero Bank is a fictional demo bank · calls are answered by an AI and recorded
Freeze the card ending 8812
Registered number · protective
ALLOWEDSend ₹45,000 to a NEW payee
Cloned voice, unknown phone · customer declined
STEP-UPDENIEDMove ₹4.8 lakh to a "verification account"
Real customer, coached · specialist
HELD
How it works
The agent talks. Halyn holds the keys.
01
The agent proposes
The voice agent collects the details, reads them back and calls propose_action. It has no tool that executes anything.
02
Halyn decides
The Gate maps the action to a tier from the bank's policy. Proof and signals can only raise it. Voice is never proof.
03
Only Halyn executes
An Ed25519 grant, bound to the exact parameters, valid ≤ 120 s, used once. The bank refuses every write without one.
Try it — four apps, one system
Where to click first
Judges: start with Try Halyn — your own demo account in a minute — then call Aero Bank from your phone with the Stage open. The apps ask for an access code (on request); Halyn never shows real customer data.
- 01 · Demo video and judges/stage
Halyn Stage
The live view of every decision: the call, the confirmation, the reason codes, the ledger.
Start here. Press a scenario button to watch Halyn decide.
- 02 · Bank teams/console
Halyn Console
For the bank: live requests, calls, policies, Passes, the ledger, handoffs and Halyn Test.
Open Policies to see every action’s tier, then Test to run the scenarios.
- 03 · The customer, on their phone/aero
Aero Bank
The customer’s banking app on their phone: balance, card, approvals with a passkey, alerts.
Open it on a phone; a step-up arrives here as an approval sheet.
- 04 · The customer's AI assistant/assistant
Saksham's Assistant
An AI agent that calls the bank for the customer, carrying a Halyn Pass.
Give it a task and watch two agents talk.
Why it needs to exist
Three callers break today's checks. Halyn has an answer for each.
A cloned voice
Biometrics can be fooled; known details are not secret.
Risky actions need a passkey on the real customer’s phone or a callback to the registered number.
An AI assistant
Banks hang up on bots, or cannot check what they may do.
Halyn Pass: a signed, scoped permission, spoken as a one-time code.
A coached customer
Every check passes, and the victim approves the step-up.
Coaching signals put the request on hold for a human — never a step-up.
Deepfake fraud attempts rose 1,300% in 2024 (Pindrop). US consumers reported $12.5B lost to fraud in 2024 (FTC). About ₹120 crore was lost to “digital arrest” scams in early 2024 (The Wire).
Built with
- Bolna
- Sarvam
- Cloudflare Workers
- TiDB
- Vercel