Model Context Protocol
The Model Context Protocol (MCP) is an open protocol developed by Anthropic that provides a standardized interface for connecting large language model (LLM) applications with external data sources, tools, and services. Released in November 2024, MCP uses a client-server architecture with JSON-RPC 2.0 messaging to establish stateful sessions between AI applications and context providers.[^c1] The protocol was inspired by the Language Server Protocol (LSP), which standardized how development tools interact with programming languages.[^c2]
MCP addresses the combinatorial complexity of integrating multiple LLMs with multiple tools, known as the "M×N problem," by providing a unified protocol that both LLM vendors and tool builders can follow.[^c3] Rather than requiring custom adapter code for each integration, MCP converts the M×N problem into a more manageable M+N problem, where a single implementation on each side enables universal interoperability. The protocol focuses solely on context exchange and does not dictate how AI applications use LLMs or manage the provided context.[^c4]
The protocol ecosystem includes the MCP specification, official SDKs for TypeScript, Python, Java, Kotlin, C#, Swift, Rust, and Dart, development tools such as the MCP Inspector, and reference server implementations.[^c7] By March 2025, over one thousand community-built MCP servers and thousands of MCP-integrated applications had been deployed.[^c5] By December 2025, the ecosystem had grown to over 10,000 active public MCP servers and 97 million monthly SDK downloads, with the protocol accumulating over 37,000 GitHub stars in under eight months.[^c11][^c9][^c10] By April 2026, monthly SDK downloads had reached 110 million — a milestone that took React three years to achieve.[^c16] On December 9, 2025, Anthropic transferred stewardship of the protocol to the Agentic AI Foundation (AAIF) under the Linux Foundation, with founding members including Amazon, Anthropic, Block, Bloomberg, Cloudflare, Google, Microsoft, and OpenAI.[^c6][^c8] The AAIF added 97 new organizations in early 2026, and the first MCP Dev Summit was held in New York City in April 2026 with approximately 1,200 attendees.[^c12][^c13] MCP Apps, released in January 2026, extended the protocol to support interactive UI components through sandboxed iframes, and the gateway architecture emerged as the dominant approach for enterprise MCP deployments.[^c14][^c15] A specification update planned for June 2026 will introduce stateless server support for horizontal scalability along with server-initiated triggers, streaming tool results, and reusable skills.[^c17][^c18]
Connections
- [[concepts/architecture|Architecture]]
- [[concepts/core-primitives|Core Primitives]]
- [[concepts/security|Security]]
- [[concepts/mcp-apps|MCP Apps]]
- [[companies/agentic-ai-foundation|Agentic AI Foundation]]
- [[protocols/mcp-vs-function-calling|MCP vs Function Calling]]
- [[protocols/mcp-vs-a2a|MCP vs A2A]]