Self-Hosted MCP: Building a Model Context Protocol Server in PHP

Short summary

The article explains how to build a Model Context Protocol (MCP) server in PHP, emphasizing that MCP is a wire protocol (JSON-RPC 2.0) rather than a language-specific library. It covers the three server primitives — tools (model-controlled actions), resources (application-controlled data), and prompts (user-invoked templates) — and the two transport options: stdio for local subprocess communication and Streamable HTTP for remote deployments. The piece includes practical PHP-specific pitfalls like avoiding stray stdout output and disabling output buffering.

• •MCP is a JSON-RPC 2.0 wire protocol implementable in any language, including PHP
• •Three primitives: tools (model-controlled), resources (app-controlled), prompts (user-invoked)
• •PHP-specific gotchas: never write non-protocol output to stdout, disable output buffering

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