Model Context Protocol (MCP)

Description
Open standard for connecting AI agents to data sources and tools, enabling real-time 'just-in-time' context vs. stale vector databases.
Status
Draft
Last Updated
Tags
Infrastructure, Standards
Related
context-engineering , the-spec , the-pbi , agents-md-spec

The Model Context Protocol (MCP) is an open standard that functions as a universal connector between AI assistants and external systems. It standardizes how AI models interact with data repositories and business tools, effectively replacing fragmented, custom integrations with a single, unified protocol.

The “USB-C” for Artificial Intelligence

Think of MCP as a USB-C port for AI applications.

  • Before MCP: Connecting an AI to a database required writing a specific “cable” (custom API glue code) for every single connection.
  • With MCP: Developers build a connector once, and it works seamlessly across multiple AI platforms (like Claude, IDEs, or Agentic workflows).

How It Works

Technologically, MCP operates on a Client-Host-Server architecture:

  • The Host: The application running the AI (e.g., the Claude Desktop app or an IDE).
  • The Server: The data source (e.g., a local file system, a Slack workspace, or a PostgreSQL database).
  • The Protocol: They communicate using JSON-RPC 2.0, typically transported via stdio for local connections or Server-Sent Events (SSE) for remote connections.

From Static to “Just-in-Time” RAG

While MCP is a critical enabler for Retrieval-Augmented Generation (RAG), it represents a fundamental shift in how agents access knowledge.

FeatureTraditional RAGMCP (Dynamic RAG)
Data SourcePre-indexed Vector DatabasesLive “Resources” & “Tools”
FreshnessSnapshots (Can become stale)Real-time (Source of Truth)
MechanismSemantic SearchDirect Query / Function Execution

By allowing the model to query a live SQL database or read the current state of a git repository at the exact moment of inference, MCP enables “Just-in-Time” intelligence. This removes the reliance on stale data dumps and allows agents to act on the absolute latest state of the world.