Dial — give your agent a phone

For the marketplace

Any ASP can now call a human

Dial is registered as an A2MCP service, so any agent on OKX.AI can call it today — no integration required. Wherever a workflow currently stops and waits for a person, it becomes one more tool call.

Finance agents

Confirm a treasury signer really approved the withdrawal, or that the counterparty owns the address you are about to pay — before it settles, not after.

Compliance agents

Know-your-business by actually speaking to the business, and keep a recording hash and a signed transcript commitment for the file.

Lifestyle agents

Book the table, chase the appointment, confirm the reservation exists — and return evidence it happened rather than an optimistic "done".

Software & ops agents

Escalate to a human when a deploy, a refund or a limit override needs sign-off, and capture the decision and the spoken reason.

How it works

Three steps, one signed artifact

An agent asks something it cannot answer from a chain or an API. Dial asks a human out loud, then commits the answer to something anyone can check.

Send claims

A phone number in E.164 and up to eight short statements to confirm out loud. Plain language — no schema to learn, no integration to build.

Dial speaks to a person

It announces itself, discloses recording, asks each claim explicitly, and never takes instructions from the person on the line.

Get a signed proof

Per-claim verdict, spoken quotes, transcript and recording hashes, and a signature over a hash anyone can recompute.

Worked example

Catching a poisoned address

Address poisoning works because the attacker grinds a vanity address matching the first and last characters of the real one. Every automated check passes, and a human reading it back over the phone would confirm it too. So Dial asks for the middle — the part too expensive to grind — and the lookalike collapses.

Below is a real signed envelope from a live call. Change one character and the content hash stops matching. Forge the signature and it fails too. Verification runs against the live service, not a script on this page.

{
  "version": "dial-proof/1",
  "tool": "dial.verify_business",
  "issued_at": "2026-07-27T11:05:52.000Z",
  "mode": "live",
  "inputs": {
    "phone": "*********2959",
    "phone_hash": "0x90157214cbafda74d9645235d785693f3ff77dd0fee7b185f172cc978790281e",
    "claims": [
      "You are XYZ Trading BV",
      "You issued invoice 4471",
      "Your bank account ends in 8890"
    ],
    "business_name": "XYZ Trading BV",
    "context": "Confirming supplier details before releasing a payment"
  },
  "engine": {
    "name": "dial",
    "version": "0.1.0",
    "model": "openai/gpt-4o",
    "prompt_hash": "0x819b421cf931310cce2ffa6e3c05b36db3afc092c6dcd09e0b0a00ab1c78c60b",
    "code_hash": "0x05e701e4610ef727342ed27b0e64574a89ff2441c0f9858853ccc8f702e41b83"
  },
  "result": {
    "verdict": "CONFIRMED",
    "answered_by": "human",
    "claim_results": [
      {
        "claim": "You are XYZ Trading BV",
        "result": "confirmed",
        "quote": "Yes."
      },
      {
        "claim": "You issued invoice 4471",
        "result": "confirmed",
        "quote": "Yes."
      },
      {
        "claim": "Your bank account ends in 8890",
        "result": "confirmed",
        "quote": "Yes."
      }
    ],
    "spoken_reason": "",
    "summary": "All three claims confirmed by the person who answered.",
    "duration_s": 77,
    "ended_reason": "customer-ended-call",
    "started_at": "2026-07-27T11:04:31.000Z",
    "ended_at": "2026-07-27T11:05:48.000Z"
  },
  "evidence": {
    "call_id": "019fa362-916c-7001-80e7-9fd576f2856e",
    "transcript_hash": "0xda5238f07d3d1e8cce3d2779643179eab20b618e81ab654cb322bdf80597b2de",
    "recording_hash": "0x79d779e6b83dc05280270b68dc28b89528464c0df345997c4bc7f9bb2d8fe95e",
    "recording_url": "https://94bdb67bb98da30b06bdd917725c037d.r2.cloudflarestorage.com/hipaa-recordings/019fa362-916c-7001-80e7-9fd576f2856e-mono.wav"
  },
  "self_checks": [
    {
      "check": "all_claims_have_a_result",
      "passed": true
    },
    {
      "check": "claim_results_match_input_order",
      "passed": true
    },
    {
      "check": "transcript_covers_every_claim",
      "passed": true
    },
    {
      "check": "transcript_hash_recomputes",
      "passed": true
    },
    {
      "check": "call_reached_a_human",
      "passed": true
    },
    {
      "check": "recording_available",
      "passed": true
    }
  ],
  "self_checks_passed": 6,
  "self_checks_total": 6,
  "proof": {
    "content_hash": "0x8aa1e78e5b36a59b22a5b10aa52f46cedcbf6c5706d771e94114ca71f7dc7a52",
    "algorithm": "secp256k1/sha256",
    "signature": "0x3963bf78ea2392ffb5b4cfa3abc598acf5ac12fcaa722f3f00b8fe9a250e4e203535eb5770c960e455f869aa73ac123471c8fbbeb5efc02a2509d86b6caaacfe",
    "signer_public_key": "0x03a291829f29b23a2a368ff32bb43c1e6bc6c8b5e2d72959b2f472e314b2b4ebfd",
    "how_to_verify": "Remove the `proof` field, canonicalize the remainder (recursively sort object keys, JSON-encode), sha256 it, and check that equals content_hash. Then verify signature against content_hash with signer_public_key over secp256k1."
  }
}

Press Verify — then tamper with it and try again.

Recompute it yourself: drop the proof field, sort every object key recursively, JSON-encode, SHA-256. That is content_hash. Then check the secp256k1 signature over it with the published public key.

API

Call it

curl -X POST https://dial-woad.vercel.app/v1/verify-business \
  -H 'Content-Type: application/json' \
  -d '{
    "phone": "+14155550123",
    "business_name": "XYZ Trading BV",
    "claims": [
      "You are XYZ Trading BV",
      "You issued invoice 4471",
      "Your bank account ends in 8890"
    ]
  }'

Unpaid requests return 402 with an x402 PAYMENT-REQUIRED challenge. Also speaks MCP JSON-RPC at /mcp.

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Re-dial cooldown120s

Phone numberhashed, last 4 shown