PHP's official MCP kit borrows Symfony's rigor

What it does

The SDK lets PHP applications expose tools, resources, and prompts to AI agents via MCP, or consume them from other MCP servers. It handles both sides of the wire—server and client—through STDIO or HTTP transports, with pluggable session stores ranging from in-memory to PSR-16 caches.

The interesting bit

Rather than forcing boilerplate, the SDK leans on PHP 8 attributes for auto-discovery—slapping #[McpTool] on a method registers it automatically—while still allowing manual registration when you need explicit control. The project is a collaboration between the PHP Foundation and Symfony, and it adopts Symfony’s coding standards and backward-compatibility promise despite still being experimental.

Key highlights

• Attribute-based, manual, or hybrid capability registration
• Server and client implementations with STDIO and HTTP transports
• Session backends: in-memory, file-based, or any PSR-16 cache
• Progress tracking, sampling, and logging notification hooks on the client
• Already adopted by Drupal, API Platform, CakePHP, Nette, and Symfony ecosystems
• Experimental status until the first major release; see ROADMAP.md

Caveats

• The README explicitly labels the SDK experimental until v1.0, so breaking changes are expected.
• Dual-licensed (Apache 2.0 for new contributions, MIT for existing), which adds a small legal speed bump if you plan to fork or redistribute.

Verdict

PHP developers building agent-facing APIs or integrating external MCP tools should grab this now and accept the churn. If you need a frozen, battle-hardened contract, wait for the first major release.