PayPack Value Metadata Specification (PVM)

The Valuation & Trust Overlay for Agentic Payments

PVM defines how AI agents, merchants, and payment facilitators express and consume value signals during agentic payments:

• 📊 Price Index: is this price fair?
• 🛡️ Credit Score: is this merchant trustworthy?
• ⭐ Feedback Aggregate: what do other buyers say?
• 🚦 Risk Level: should this payment be allowed?

PVM sits ON TOP of x402 / AP2 / Alipay / WeChat.
It does NOT replace payment protocols — it enriches them with machine-readable trust signals.

x402 V2 defines maxAmountRequired in the 402 response — but doesn't answer "is this amount reasonable?"
PVM fills this gap as a protocol-agnostic valuation overlay.

📄 Current Specifications

1. PVM Core (JSON Schema) 🆕

• Status: Active (v0.1.0)
• Scope: Core Value Metadata structure — embeds price index, credit score, and feedback into x402/AP2 payment responses.
• Files:
  • /schemas/v1/value-metadata.json — Core PVM schema
  • /schemas/v1/price-index.json — Price index sub-schema
  • /schemas/v1/credit-score.json — Credit score sub-schema

2. AI Agent Credit Scoring Standard v1.0-draft

• Status: Draft / Community Feedback
• Scope: Defines a four-dimensional credit scoring model (300-850) for AI agents in payment scenarios.
• File: /specs/credit-scoring-spec.md

3. Service Metadata Schema (JSON Schema)

• Status: Active
• Scope: Standardized metadata for AI service evaluation (pricing, performance, reputation, SLA).
• File: /schemas/v1/ai-service-metadata.json

4. Price Index SQL Schema

• Status: Active
• Scope: DDL for price index engine, merchant credit scoring, and user feedback tables.
• File: /schemas/v1/price-index.sql

🧪 Examples

• x402 402 Response with PVM embedded 🆕 — Shows how x402 V2 payment response carries PVM trust signals
• Price Guard Hook — Fail-open price check before payment
• Schema Validator — Python validator for service metadata
• Weather API / Top-Up Service

🗺️ Roadmap

• Service Metadata Schema (v1.0)
• Price Index + Credit Score JSON Schemas (v0.1.0) 🆕
• x402 V2 + PVM integration example 🆕
• Price Index SQL Schema (v1.0)
• Credit Scoring Standard Draft (v1.0-draft)
• Price Index Methodology Specification — Q3 2026
• Trust Protocol Interoperability Standard — Q4 2026

🚧 Current Development Status (2026-08)

PVM is under active development. We are currently working on:

• Resolving weight inconsistency between credit-score.json and price-index.sql
• Defining risk_level assessment rules → specs/risk-assessment.md
• Publishing trust_score methodology specification → specs/trust-score-methodology.md
• Price Index Methodology Specification — Q3 2026
• Trust Protocol Interoperability Standard — Q4 2026

For detailed audit findings, see AUDIT-2026-08.md.

🤝 Contributing

This is a community-driven effort. We welcome feedback, issues, and pull requests from developers, platforms, and researchers across the AI and payments ecosystem.

See CONTRIBUTING.md for guidelines.

1. Read the draft specification
2. Open an Issue for feedback
3. Submit a Pull Request for improvements
4. Join the Discussions

📧 Contact

Maintainer: rhcjw

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Together, let's build the trust layer for AI agent payments. 🛡️