PROTOCOL STACK
The Protocol Stack
Four open specifications doing four jobs. Aethelforge speaks all of them because the industry will not consolidate on one.
THE ANSWER
Which protocols does Aethelforge support?
Aethelforge supports four open agent-commerce protocols: MCP (tool-calling context), ACP (commerce handshake), AP2 (agent payment authorization), and x402 (HTTP-native micropayments). Each does one job; together they form the complete stack for gated machine-to-machine transactions.
Model Context Protocol
Standardized tool-calling surface between LLMs and external data sources.
Agentic Commerce Protocol
Cryptographic handshake for machine-to-machine commerce transactions.
Agent Payments Protocol
Agent-mediated payment authorization and settlement protocol.
HTTP 402 Native Payments
HTTP-native micropayments using the long-dormant 402 status code.
Why four
Because they do different jobs. MCP standardizes how a model discovers and calls your capabilities — it's a context protocol, not a commerce one. ACP handles the commerce-specific handshake when negotiation is required. AP2 answers “how do we know this agent is allowed to spend this money?” x402 answers “how do we settle small amounts inline with an HTTP response?” Any real agent transaction uses a stack, not a single line.
The bet Aethelforge makes is that trying to pick one winner here is the wrong move. The industry already signals fragmentation — Anthropic, OpenAI + Stripe, Google, and Coinbase all backing different pieces of the stack. The right position is to speak all of them fluently and translate at the gate.
Start here
If you're a merchant, the protocol you care about first is ACP — it's the one that defines the commerce handshake. If you're building an agent, start with MCP and then add commerce support through whichever of the others fits your use-case. If you're a finance or compliance person, go straight to AP2 — it's the only one that answers your questions head-on.
FAQ
Protocols, answered.
01Why support four protocols instead of picking one?
Because each one does a different job. MCP is a context protocol — how a model discovers and invokes tools. ACP is the commerce handshake when negotiation is required. AP2 answers authorization — proving the agent is allowed to spend. x402 is HTTP-native settlement. A real transaction uses a stack, not a single line.
02Which protocol should a merchant implement first?
ACP. It defines the agent-commerce handshake that lets agents discover your catalog, negotiate terms, and confirm an order. MCP describes your tools to the agent; ACP is what actually closes the transaction. AP2 and x402 layer on top for authorization and settlement.
03Who stewards each protocol?
MCP is stewarded by Anthropic. ACP is a joint OpenAI + Stripe specification. AP2 is driven by Google. x402 was introduced by Coinbase as an open HTTP-native payment standard. Aethelforge is neutral — we speak all four and translate at the gate.
04Is Aethelforge replacing these protocols?
No. Aethelforge orchestrates across them. The protocols are open standards we consume and emit. Aethelforge is the trust layer — cryptographic receipts, idempotency, settlement trail — that makes a multi-protocol handshake auditable end-to-end.