How I Started Building an MCP Server in Bash — and Discovered the Simplicity of JSON-RPC

We often think APIs need frameworks — express(), @RestController, GraphQL, etc. I thought the same when I first saw the Model Context Protocol (MCP) used by tools like Copilot and Claude.

But I couldn’t grasp it by reading libraries. So I tried building an MCP server from scratch — in Bash.

That led me to discover JSON-RPC, a protocol that’s surprisingly minimal and elegant.

In this talk, I’ll walk through that journey — understanding stdio vs CLI, decoding JSON-RPC basics, and how removing layers of abstraction helped me see what’s really happening.

This isn’t about Bash. It’s about learning protocols by building them — something you can do in JS, Go, Python, or anything once you get the idea.

• What JSON-RPC really is — without frameworks

• How stdio app is different from command line app

• What MCP is and how tools like Copilot/Claude use it

• Why writing from scratch (even in Bash) helps understand better

• How you can build your own MCP server in any language