TechnicalWhitePaper

Technical White Paper (Zen7 Payment Agent)

1. Abstract and Overview

Zen7 Payment Agent stands as the inaugural practical implementation of the DePA (Decentralized Payment Agent) framework, pioneering the next generation of intelligent payment infrastructure. It not only fully realizes the core functionalities of DePA but has also been successfully deployed with innovative application cases within the field of agent-enabled e-commerce.

As the first practical project within the DePA ecosystem, Zen7 achieves several key characteristics: automated encrypted payments among intelligent agents, an "authorized password-free" mechanism, and intent recognition and interaction powered by large language models.

By supporting multi-chain, multi-wallet, and multi-currency operations, integrating robust security mechanisms, and delivering an exceptional user experience, Zen7 Payment Agent establishes a seamless "intent-to-result" payment journey.

2. Technical Architecture

Zen7 Payment Agent employs a multi-agent collaborative architecture designed to deliver a comprehensive payment solution. It provides support for both A2A (Agent-to-Agent) and MCP (Model Context Protocol) protocols, enabling seamless communication and integration within decentralized ecosystems. The architecture natively supports both custodial and non-custodial fund management models, offering flexibility to accommodate diverse application requirements and user preferences for asset control.

This architecture is engineered to provide a multi-chain, multi-currency, and multi-wallet payment solution specifically for AI Agents and native DApps. It is capable of handling high-frequency transactions while incorporating features such as a "authorized password-free" mechanism and solutions for gas fee abstraction, thereby creating a seamless and efficient payment experience from intent to result.

2.1 Multi-Agent Collaborative Architecture

Zen7 Payment Agent employs a "1+3" multi-agent collaborative architecture to implement decentralized payment processes. Within this framework, the Host Agent acts as the core coordinator, responsible for intent comprehension, intelligent routing, state management, risk control, and auditing . Three specialized agents operate with distinct responsibilities: the Payer Agent handles payment capability assessment, credit authorization checks, and the generation of signatures based on the EIP-712 standard; the Settlement Agent functions as the on-chain execution engine, completing processes such as risk control, authorization, and fund transfer, while supporting both custodial and non-custodial models ; and the Payee Agent is tasked with payment receipt confirmation, settlement record generation, and fund management. The complete payment flow is as follows: the Host Agent routes the payment request → the Payer Agent performs validation and generates signatures → the Settlement Agent executes the on-chain settlement → the Payee Agent confirms receipt of funds. This sequence forms an end-to-end automated closed loop. Building on this collaboration, the service agent layer exposes user-facing capabilities.

Beyond the core multi-agent architecture, Zen7 Payment Agent provides a comprehensive suite of supporting services designed to ensure compliance, observability, and operational efficiency. These services are fundamental to the platform's security, auditability, and manageability in a production environment.

Notification & Alerting Service: This service offers event subscription and push notifications for both end-users and various intelligent agents. It supports multi-channel integration, ensuring timely dissemination of critical information related to transaction status, system events, or potential risks.
Risk Control Engine: The engine performs real-time transaction interception based on a combination of configurable policies, including quota limits, address whitelists, and on-chain risk scoring modules. All enforcement decisions are logged, providing a clear and auditable trail for risk management activities.
Event Monitor: This component continuously monitors both on-chain events and interactions among the various internal agents. It writes these events to immutable audit logs and the internal ledger. The monitor also supports alert triggering, event replay for debugging, and comprehensive compliance tracing.
Audit Log & Ledger: This service meticulously records critical data points, including onchain transaction hashes, permission usage, approver signatures, and reconciliation vouchers. This creates a dual-ledger system that synchronizes on-chain records with offchain audit data, ensuring a complete and tamper-evident record of all activities.
Policy & KYX Service: Providing a unified compliance framework that covers KYC (Know Your Customer), KYS (Know Your Supplier), and KYA (Know Your Agent), this service performs identity verification and risk assessments for customers, merchants, and intelligent agents. It underpins transaction policies, manages whitelists and blacklists, and conducts necessary compliance checks.

2.2 Custodial Mode

In Custodial Mode, the Host Agent completes intent validation and triggers the Payer Agent to perform an on-chain balance check and generate an EIP-2612 Permit signature. The Settlement Agent verifies the signature, pays the gas fee, executes permit + transferFrom operations, transfers funds into a designated escrow wallet, and records the transaction in real-time. Funds are protected by risk control policies during the custodial period. Upon reaching settlement conditions, funds are released to the Payee Agent after review. The Event Monitor and Audit Log & Ledger maintain records; contingency procedures (re-authorization, interception, arbitration, refunds) are available for anomalies.

A key feature: the Settlement Agent covers Gas fees uniformly, providing a "Zero-Gas" payment experience for both Payer and Payee across custodial and settlement phases.

The Zen7 Payment Agent operational workflow is a sequence of discrete, automated steps. The following stepper details the flow from intent initiation to final settlement and auditing.

Intent & Validation

Host Agent receives the payment request and performs initial validation of parameters (asset, amount, validity period). On success, it creates a unified Payment Agent Context and routes the request.

Balance Check

Payer Agent queries on-chain balance to verify sufficiency. If sufficient, proceed. If insufficient, workflow terminates with an error and requires re-initiation.

Signature Processing

Payer Agent requests a signature from the connected wallet to generate EIP-712 structured signature data compliant with EIP-2612 Permit. On failure, the workflow terminates with an error.

Authorization Request Submission

Payer Agent submits the authorization and payment request (including signature data) to the Settlement Agent.

Authorization & Transfer (Escrow Funding)

Settlement Agent uses EIP-2612 Permit to execute authorization. Upon token contract verification, Settlement Agent calls transferFrom to transfer funds into escrow wallet. Settlement Agent covers Gas fees. On failure, workflow terminates with an error.

Escrow Confirmation

Settlement Agent confirms escrow transaction success and records escrow details; funds enter a holding period under escrow protection per business rules.

Settlement Processing

When settlement conditions are met, Settlement Agent performs final risk and compliance checks and transfers funds from escrow wallet to Payee. If settlement fails, exception handling is triggered. Settlement Agent covers Gas fees.

Settlement Confirmation & Auditing

Settlement Agent confirms settlement; Payee Agent receives payment confirmation. Event Monitor captures events from escrow and settlement phases; Audit Log & Ledger record the complete transaction link, creating an immutable and auditable trail.

If exceptions occur at any stage, the system supports re-authorization, policy-based interception, dispute arbitration, and refunds.

The payment sequence diagram illustrates the message and data flow among the multiple agents across the stages of Intent → Sign → Payment → Settlement.

Funds Transfer Phase: This phase encompasses the critical steps from intent validation to the successful escrow of funds.

Settlement Phase: This phase involves the release of funds from escrow to the Payee upon meeting predefined conditions.

All state changes generate on-chain events captured by the Event Monitor and written into the Audit Log & Ledger, forming a replayable evidence chain. Key events include:

Event Name

Trigger Point

Corresponding Workflow Stage

Purpose

IntentCreated

T0 - Payment intent creation

Intent & Validation

Records origin and parameters of the payment request.

PermitSigned

T2 - Signature generation

Signature Processing

Records the EIP-2612 Permit signature data.

FundsEscrowed

T4 - Funds placed in escrow

Authorization & Transfer

Marks transfer of funds into escrow wallet.

FundsReleased

T6 - Funds released

Settlement Processing

Marks transfer of funds from escrow to Payee.

SettlementCompleted

T7 - Settlement confirmed

Settlement Confirmation

Confirms Payee has received funds; payment completion.

TransactionFailed

Transaction failure

Exception Handling

Records reason for failure.

DisputeInitiated

Dispute initiated

Exception Handling

Triggers freezing of escrowed funds pending arbitration.

2.3 Non-Custodial Mode

In the Non-Custodial Mode, the operational workflow is as follows: the Host Agent first completes intent validation and triggers the Payer Agent to perform an on-chain balance check and generate an EIP-2612 Permit signature. The Settlement Agent then verifies the signature, pays the Gas fee required for the transaction, and executes the permit+ transferFromoperations. This results in the direct transfer of funds from the Payer's wallet to the Payee's wallet. Upon successful transfer, the transaction is recorded in real-time. Throughout this entire process, the Event Monitor and Audit Log & Ledger maintain comprehensive records. Should any anomalies occur, predefined contingency procedures—such as re-authorization, transaction interception, arbitration, or refunds—are automatically triggered.

A defining characteristic of the Non-Custodial Mode is that the Settlement Agent covers the Gas fees specifically for the on-chain transferFromoperation during the fund transfer phase. This mechanism ensures that both the Payer and the Payee experience a seamless, "Zero-Gas" transaction from initiation to completion, eliminating the financial and operational burden of blockchain transaction fees for the end-users.The operational workflow for the Non-Custodial Mode, where funds are transferred directly from the Payer to the Payee, consists of the following sequenced stages: