ap2-risk-signals

AP2 Risk Signals Framework

Before writing code

Fetch live docs:

1. Fetch https://ap2-protocol.org/specification/ for risk payload specification
2. Fetch https://ap2-protocol.org/topics/privacy-and-security/ for risk considerations
3. Web-search ap2 protocol risk signals fraud agentic payments for risk framework details
4. Web-search site:github.com google-agentic-commerce AP2 risk for implementation references

Conceptual Architecture

Why Risk Signals Matter

Agentic commerce introduces novel risk dimensions that traditional payment systems weren't designed for. AP2's risk signals framework provides a common language for all ecosystem participants to assess transaction risk.

Novel Agentic Risk Factors (from the official AP2 risk factor table)

Risk Factor	Description
User asynchronicity	User may not be present during the entire transaction journey
Delegated trust	Agents initiate transactions on behalf of users
Mandate-merchant matching	Verifying the purchase matches the authorized intent
Temporal gaps	Time between token generation and payment execution
Indirect trust establishment	CP and Merchant may not have a direct trust relationship
Agent identity verification	Verifying the agent is who it claims to be

Additional AI-Specific Risks (not from the official AP2 risk factor table)

The following are additional AI-specific risk considerations relevant to agentic commerce implementations, but they are not part of the official AP2 specification's novel risk factor table:

Risk Factor	Description
Agent hallucination	AI agent may misinterpret user intent
Prompt injection	Malicious inputs that manipulate agent behavior

Risk Payload

The risk payload is an open-ended field structure in V0.1:

• Intentionally flexible for industry-specific risk signals
• Allows Credentials Providers, Merchants, and Networks to pass custom risk data
• Each actor contributes their own risk assessment signals
• The payload travels with the mandate through the transaction flow

Risk Assessment by Role

Shopping Agent

• Quality of intent capture (how clearly the user expressed their intent)
• Session authentication strength
• User behavioral signals

Credentials Provider

• Payment method risk level
• User account history
• Device trust score
• Previous transaction patterns

Merchant

• Order anomaly detection
• Intent-to-cart matching confidence
• Fulfillment risk assessment

Network/Issuer

• Card risk signals (fraud patterns, velocity checks)
• 3DS challenge decisions
• Authorization risk scoring
• AI involvement context (from Payment Mandate)

Trust Establishment

AP2 defines trust establishment phases:

Short-term (V0.1):

• Manually curated allowlists per entity
• Known partner relationships
• Pre-configured trust

Long-term (future):

• Real-time trust via HTTPS certificate validation
• DNS ownership verification
• mTLS (mutual TLS) for strong identity
• API key exchange
• Identity assertions in A2A/MCP protocols
• Agent reputation systems

Dispute Risk Assessment

For dispute resolution, risk signals help determine accountability:

• Strong user authentication → lower risk of ATO (account takeover)
• Clear Intent Mandate → lower risk of agent mispick
• Valid merchant signature → merchant committed to terms
• Matching mandate vs delivery → no fulfillment fraud

Best Practices

• Include as many risk signals as available — more data helps better assessment
• Don't rely solely on LLM output for risk signals — use deterministic checks
• Validate agent identity cryptographically, not just by self-declaration
• Monitor for prompt injection in shopping intent
• Track temporal gaps between intent capture and payment
• Build risk scoring models specific to agentic transactions
• Log all risk signals for post-transaction analysis
• Implement anomaly detection for unusual agent behavior patterns
• Update risk models as agentic commerce patterns emerge

Fetch the specification for exact risk payload structure, supported signal types, and risk assessment requirements before implementing.