MCP is an open JSON-RPC protocol that lets any LLM host plug into any tool, data, or prompt server without writing custom integration code per vendor.
Imagine if every electronic device had its own special charger shape, your phone, your laptop, your headphones, all different plugs. That's what LLM app development was like before MCP. Every chatbot had to write custom code to connect to every tool: one wrapper for the database, another for GitHub, another for your file system. MCP is the USB-C of LLM tooling. Anyone can build an MCP server for a service, and any compliant host, Claude Code, Cursor, Zed, can plug it in. The server says, 'here are my tools, here is my data, here are my prompts,' and the host wires those into the LLM. One protocol, many servers, many hosts.
Detailed answer & concept explanation~4 min readEverything you need to truly understand this topic: intuition, mechanics, step by step explanation, code, formulas, and worked example. Click to expand.
Everything you need to truly understand this topic: intuition, mechanics, step by step explanation, code, formulas, and worked example. Click to expand.
Everything you need to truly understand this topic: intuition, mechanics, step by step explanation, code, formulas, and worked example.
Everything important, quickly.
3 min: three primitives + two transports + discovery flow + how MCP composes with function calling + which hosts shipped clients.
Real products, models, and research that use this idea.
- Claude Code uses MCP to load filesystem, GitHub, and shell tools, all servers Anthropic ships in the public registry.
- Cursor and Zed both added MCP clients in 2025 so any Claude-Code-compatible server works in their editors.
- Anthropic's MCP server registry catalogs community servers for Postgres, Slack, browser automation, and Notion.
What an interviewer would ask next. Try answering before peeking at the approach.
QHow does an MCP host handle servers it doesn't fully trust?
QWhat changes when the server is remote instead of local?
Don't say thisRed flags and common mistakes that signal junior thinking. Click to expand.
Red flags and common mistakes that signal junior thinking. Click to expand.
Confusing MCP with function calling. Function calling is the model's tool-output shape; MCP is the host to server transport protocol.
The night-before-the-interview bullets. Scan these on the way to the call.
Primary sources. Skim if you want the original framing.
Same topic, related formats. Practice these next.