标签：#forge

Every AI agent ships with the same bottleneck: it can only reason over what it can reach. MCP servers dissolve that boundary. They expose tools, resources, and prompts to any compliant client over a JSON-RPC wire format so lean you can implement it in an afternoon. Yet most developers grab a framework, copy a template, and ship something they can barely debug. Forge starts differently. You will build an MCP server from the bare protocol up, understand every byte on the wire, and gain the mental model that makes every future server trivial. The Idea (60 Seconds) MCP is a JSON-RPC 2.0 protocol. A client sends a request. Your server returns a response. Three request types power the core loop: initialize , handshake. Client and server exchange capabilities. tools/list , discovery. Server returns every tool it offers, each with a JSON Schema describing its inputs. tools/call , execution. Client names a tool and passes arguments. Server runs the handler and returns structured content. Transport is either stdio (JSON-RPC over stdin/stdout) or HTTP (Streamable HTTP). Stdio is the simplest place to start: read a line from stdin, parse it, dispatch, write a line to stdout. That is the entire architecture. Everything else is error handling, schema validation, and ergonomics. Why This Matters MCP servers are the new APIs. Where REST gave machines endpoints, MCP gives agents tools with typed inputs and structured outputs. Every integration layer from IDE assistants to autonomous workflows converges on this protocol. The standard is young. The primitives are stable. The surface area is small enough to hold in your head all at once. Knowing the wire format gives you three advantages frameworks obscure: Debugging , when a tool call fails, you can read the raw JSON-RPC message and pinpoint the fault in seconds. Portability , any language, any runtime, any transport. Write a server in Bash if you want. The protocol is the contract. Evolution , MCP will add capabilities. Understanding