Every real agent project starts with the same wall: a model that can reason brilliantly but can't touch anything in the real world.
See the access gap first-hand against a real model, then understand exactly what problem the Model Context Protocol was built to solve.
What You'll Build in This Masterclass
- Why Every LLM Needs a Protocol for Tools
- MCP Is Just JSON-RPC 2.0
- Writing a Tool Schema a Model Can Actually Use
- The Tool Registry: Where Names Meet Real Code
- Serving Real Files From a Tool Handler
- Giving DevAssist Real, Mutable Task State
- Tool-Calling: Giving a Model Real Options
- Parsing a Real Tool Call Safely
- Closing the Loop: From Tool Call to Real Answer
- The Model Is Not Your Security Boundary
- Resources and Prompts: The Other Two MCP Primitives
- Shipping DevAssist to a Real Client
1. The Access Gap
A base LLM only ever sees the text in its context window. It has no filesystem, no database, no task tracker, and no way to get one — every capability beyond 'generate the next token' has to be handed to it explicitly by whatever application is calling it. Ask it to check a real file or a real task list and it can only guess, refuse, or hallucinate a plausible-sounding answer.
Before a standard existed for this, every team solved it differently: custom function-calling glue wired to one specific provider's API, one specific tool, one specific app. That code couldn't be reused between projects, and it had to be rebuilt every time a team wanted to swap models or add a tool.
2. One Protocol, Any Client, Any Server
MCP standardizes that wiring. It defines a JSON-RPC 2.0 message format for listing available tools, calling a tool with arguments, and returning results — the same format regardless of which model or which application is on the client side. Build one MCP server for your task tracker once, and any MCP-compatible AI client (Claude Desktop, an IDE assistant, your own app) can use it without custom integration code.
FAQ
Do I need to use Claude or a specific vendor's SDK to build an MCP server?
No — MCP is an open, model-agnostic protocol. Any client that speaks it (Claude Desktop, an IDE assistant, or your own app) can talk to a server you build, and the JSON-RPC message format is the same either way.
This is the first lesson of a free, hands-on, interactive masterclass — you write and run real code at every step, not just read.
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