MCP is an open Apache 2.0 protocol from Anthropic (November 2024) that standardizes how AI apps connect to tools, data, and prompts via JSON-RPC 2.0, turning M times N integrations into M plus N.
Imagine every coffee machine needing a different plug shape for the wall socket. Every kitchen would need a drawer full of adapters. MCP is the agreement that says all coffee machines (AI apps like Claude Desktop or Cursor) and all wall sockets (data sources like GitHub, your filesystem, or Postgres) use the same plug shape. The plug was designed by Anthropic in November 2024 and given away under an open license so any company can adopt it freely. Once a tool ships an MCP server, every MCP aware AI app can use it. Once an AI app speaks MCP, it can reach every existing server. The drawer of adapters disappears, and adding a new coffee machine or a new socket costs nothing extra on the other side.
Concept explanation~2 min read
Everything you need to truly understand this topic: intuition, mechanics, step by step explanation, code, formulas, and worked example. Click to expand.
Concept explanation~2 min read
Everything you need to truly understand this topic: intuition, mechanics, step by step explanation, code, formulas, and worked example. Click to expand.
MCP stands for the Model Context Protocol. It is one of the more consequential pieces of infrastructure introduced into the AI stack in late 2024, and by 2026 it has become a default assumption across every serious agent runtime.
This deep dive answers the surface question (what is MCP, who built it, when) and then unpacks why the protocol exists, what it standardizes, what it deliberately leaves out, and where it sits in the broader 2026 agent stack. The goal is a working mental model you can defend in an interview without hand waving.
The one sentence definition, unpacked
The Model Context Protocol (MCP) is an open, Apache 2.0 licensed protocol introduced by Anthropic in November 2024 that standardizes how AI applications connect to external context (tools, data sources, and prompt templates) via a client and server interface built on JSON-RPC 2.0.
That sentence carries five load bearing claims. It is a protocol, meaning a wire level specification of messages on a transport, not a library or framework. It is open, meaning the spec is published and anyone can read or implement it. It is Apache 2.0, meaning the license is permissive enough for commercial adoption without contamination concerns. It originated at Anthropic in November 2024, which dates the ecosystem. And it sits on JSON-RPC 2.0, which means each message is a small JSON object with a method, params, and either a result or an error.
The architecture follows a client and server split. The client lives inside a host application. The server runs as a separate process or service. The client opens a connection, performs an initialize handshake to negotiate capabilities, and then exchanges JSON-RPC messages to list and call tools, list and read resources, and fetch and render prompts. That is the entire conceptual model.
Situations where this technique stops working.
2–4 min · Everything important, quickly.
Real products, models, and research that use this idea.
- Claude Desktop ships with an MCP client and pre installed filesystem, fetch, and memory servers; users add more from the public registry by editing the config file.
- Cursor and Zed both embed MCP clients in 2026, so the same GitHub or Postgres server works across both editors without any host specific glue code.
What an interviewer would ask next. Try answering before peeking at the approach.
QWhy JSON-RPC 2.0 and not gRPC or a custom binary protocol?
JSON-RPC is human readable, has trivial bindings in every language, requires no schema compiler, and integrates cleanly with both stdio framing and HTTP. The byte cost is negligible compared to model inference latency.
Red flags & common mistakes
The phrases that signal junior thinking. Click to expand.
Red flags & common mistakes
The phrases that signal junior thinking. Click to expand.
Calling MCP a library or an SDK. MCP is a wire protocol that defines messages on a transport. The SDKs in Python, TypeScript, and other languages are convenience implementations, not the protocol itself.
60 second bullets to scan on the way to the call.
State the one sentence definition of MCP as an open protocol for AI tool integration
Name Anthropic as the creator and November 2024 as the announcement date
Primary sources. Browse if you want the original framing.
Same topic, related formats. Practice these next.