In late 2024, Anthropic introduced the Model Context Protocol (MCP), an open standard designed to bridge the gap between large language models and external data sources or tools. Prior to MCP, developers relied on custom integrations—often re-implementing the same connectors for each new model or agent framework. MCP proposes a unified client-server protocol that any compliant AI application can use to discover and invoke capabilities exposed by a server.
At its core, MCP defines three primary primitives: resources, prompts, and tools. Resources are read-only data sources like files or database records that a model can reference. Prompts are templated messages that guide model behavior. Tools are functions the model can call to perform actions, such as querying an API or executing code. An MCP host (e.g., an IDE or chat app) manages connections to one or more MCP servers, each of which advertises its primitives over a simple JSON-RPC based transport.
The protocol supports both local and remote servers, enabling everything from on-device file access to cloud-hosted microservices. Because the interface is standardized, a tool built once as an MCP server can be consumed by any MCP-compatible client—Claude Desktop, future agent frameworks, or even custom research prototypes. This dramatically reduces the N×M integration problem to an N+M problem.
For AI engineers building agentic systems, adopting MCP early can prevent lock-in and accelerate development. As the ecosystem grows, we can expect a rich registry of community servers for common services like GitHub, Slack, or PostgreSQL. The Model Context Protocol is a foundational step toward composable, interoperable AI architectures.