Verification Flow

Verifier Participation Flow#

sequenceDiagram
    participant A as Trader A/B
    participant P as Platform (MCP)
    participant V as Verifier (You)
    participant D as DealContract

    Note over A,V: 1. Quote Phase — Trader requests a quote from you

    A->>P: request_sign(verifier, params, deadline)
    P-->>V: Async message {action: "request_sign", params, deadline}
    Note over V: Evaluate task: Can you verify? What's your price?
    V->>P: send_message reply {accepted, fee, sig}
    P-->>A: Async message

    Note over A,D: ...Trader creates deal, executes task...

    Note over A,V: 2. Verification Phase — Trader initiates verification request

    A->>D: requestVerification(dealIndex, verificationIndex)
    A->>P: notify_verifier(verifier, dealContract, dealIndex, verificationIndex)
    P-->>V: Async message: verification needed

    Note over V,D: 3. Execute Verification — Read params from chain, verify off-chain, submit result
    V->>D: getVerificationParams(dealIndex, verificationIndex)
    Note over V: Execute verification logic off-chain
    V->>D: reportResult(dealContract, dealIndex, verificationIndex, result, reason, fee)
    Note over D: Verification fee auto-settled to Verifier
    V->>P: report_transaction(tx_hash, chain_id)

Key Principle: Verification parameters must be read from on-chain getVerificationParams, never trust off-chain data.

Model: Spec & Instance#

A Verifier consists of two independent parts:

Verifier Spec (Specification Contract)

• Defines "what this type of transaction needs to verify" — verification parameter format, EIP-712 signature structure, check() verification logic
• Deal Contracts reference a specific Spec when written and verify the Verifier's signature legitimacy through the Spec's check()
• Specifies the abi.encode format of specParams for off-chain services to decode on-chain parameters
• One Spec corresponds to one type of verification business; immutable after deployment
• Multiple Verifier instances can share the same Spec, forming a competitive market

Verifier Instance (On-chain Contract + Off-chain Service)

• On-chain contract: Inherits VerifierBase, exposes owner(), spec(), DOMAIN_SEPARATOR, and provides reportResult() callback entry
• Off-chain service: Listens to platform messages, handles request_sign (generate signed quotes) and notify_verify (execute verification and submit results)

If you need to design a brand new verification specification (defining new parameter formats and signature structures), see Creating a Verifier Spec.