PROTOCOL · MCP
MCP — Model Context Protocol
The standardized tool-calling surface between large language models and external data sources. Aethelforge speaks MCP natively.
THE ANSWER
What is the Model Context Protocol (MCP)?
The Model Context Protocol (MCP) is an open specification from Anthropic that standardizes how LLMs call tools and fetch context from external servers. It gives any MCP-aware model access to any MCP-compliant server — eliminating the one-off integration work that used to ship with every LLM deployment.
What MCP actually is
Before MCP, every model vendor ran their own tool-calling dialect. OpenAI had function calling, Anthropic had tool_use, Google had function declarations, and the agent tooling ecosystem was fifty thousand lines of glue code all doing roughly the same thing. If you wanted to plug a model into a new data source, you rebuilt the bridge from scratch.
MCP replaces that with a single wire format. A model — or more specifically, the client running on the model's behalf — speaks MCP to a server that exposes resources, tools, and prompts. The server can be your filesystem, your CRM, your product catalog, a git repo, or anything else. The client does not need to know how any of it works. It just asks.
The wire
MCP is JSON-RPC over a transport. Originally stdio (for local servers), then HTTP with Server-Sent Events for remote. The model sends requests — list_resources, read_resource, call_tool— and the server responds with structured results the model can reason over. There's a capability handshake up front, so each side declares what it supports before any real work happens.
The point of the handshake is not elegance. It is legibility. If every merchant in the agent economy spoke a different dialect, every agent would require a different client. MCP collapses that to one.
How Aethelforge uses it
Aethelforge exposes its core capabilities — catalog discovery, intent signing, handshake initiation, settlement lookup — as MCP resources. An agent that already speaks MCP (meaning, essentially every agent framework shipping today) gets access for free.
Specifically:
aethelforge://catalog/{domain}returns the live agent-commerce manifest for any domain running Forge SDK.aethelforge://handshakeis a tool that kicks off a signed intent handshake and returns the resulting receipt URL.aethelforge://settlements/{receipt_id}returns settlement state and the on-chain or off-chain reference.
You can call those from Claude, from ChatGPT with an MCP adapter, from a custom LangChain agent, from a Python notebook. MCP is the surface; Aethelforge is the gate behind it.
The part nobody mentions
MCP is a context protocol. It is not a commerce protocol, not a payments protocol, and not an identity protocol. It carries your intent to the server; it does not sign it, settle it, or audit it. For that, Aethelforge composes MCP with ACP (the commerce handshake) and x402 (the settlement rail). Three protocols, one gate.
This is the right decomposition. MCP's job is to make your merchant legible. The rest of the stack is what makes the transaction gated.