Whitepaper V4.1
9. MCP, A2A and Open Agent Interoperability
IONON should not create a proprietary protocol for every integration layer.
MCP is the vertical tool/context layer. The July 28, 2026 specification introduced a stateless protocol core, authorization hardening, an extension framework and updated SDKs. IONON’s MCP Gateway can expose wallet, policy, payment and data tools through one controlled interface while preserving least privilege and auditable authorization.
A2A is the horizontal agent-to-agent layer. A2A v1.0 is production-ready and explicitly complements MCP: MCP connects an agent to tools and context; A2A allows independent agents to discover one another, advertise capabilities through Agent Cards, exchange messages and manage tasks.
IONON’s native differentiator is not replacing MCP or A2A. It is adding identity + delegated authority + economic policy + settlement + evidence around them.
ERC-8004 is also relevant as an Ethereum draft for trustless agent discovery, reputation and validation. Because it remains a draft, it should be treated as an interoperability target, not as a dependency that defines IONON’s identity model.
9.1 Standards stack for economic agents
IONON should reuse mature identifiers and signature standards wherever possible:
- W3C VC 2.0 for portable, machine-verifiable credentials and the Agent Birth Certificate envelope;
- CAIP-2 / CAIP-10 for chain-agnostic chain and account identifiers across Ethereum, Cosmos and future networks;
- SIWE / ERC-4361 for human-controlled Ethereum authentication to web services;
- EIP-712 for typed, domain-separated authorizations such as Orders, Mandates and policy updates;
- ERC-1271 for validating signatures issued on behalf of contract accounts, DAOs and smart wallets;
- ERC-4337 and EIP-7702 as optional account-abstraction/delegation building blocks where they improve recovery, scoped execution and sponsored transactions without weakening policy controls;
- x402 as a machine-payment interface for API/service access; x402 v2 adds wallet identity, discovery and CAIP-based multi-network support;
- Visa Trusted Agent Protocol, Mastercard Verifiable Intent/Agent Pay and Circle Agent Stack as external evidence that identity, intent, controls, spending policies and machine-readable payment rails are becoming independent infrastructure categories in agentic commerce.
IONON does not need to win by inventing every wire protocol. It wins if an agent can arrive through open standards and still obtain one consistent IONON treatment for identity, delegated authority, policy, settlement and evidence.
9.2 Authorization envelope
An economic authorization should be signable as structured data and include at minimum: principal, agent, chain/account identifiers, nonce, issue/expiry times, action class, asset/value ceilings, counterparty scope, tool scope, policy version and evidence destination. Replay prevention belongs to the Order state machine, not to user memory. A signature proves that someone authorized a message; the Policy Engine still decides whether that authorization is currently sufficient.