MCP SDK for PHP

Working examples for building MCP servers and clients with logiscape/mcp-sdk-php v2. Every example targets the 2026-07-28 MCP specification revision by default while remaining interoperable with legacy clients and servers (2024-11-05 … 2025-11-25) through the SDK's automatic dual-era negotiation.

Unless a command says otherwise, run the examples from the repository (or your project) root so vendor/autoload.php resolves.

Getting started

Example	Demonstrates
simple_server.php	The minimal McpServer: one tool, run() auto-selects stdio (CLI) or HTTP (web SAPI)
simple_server_stdio.php	Same server forced onto the stdio transport with runStdio()
simple_server_http.php	Same server forced onto the HTTP transport with runHttp()

# stdio (for MCP hosts that spawn a local process)
php examples/simple_server.php

# HTTP (development server; on real hosting just upload the script)
php -S localhost:8000 examples/simple_server_http.php

# inspect either with MCP Inspector
npx @modelcontextprotocol/inspector

The 2026-07-28 stateless revision

Example	Demonstrates
stateless_server.php	A minimal stateless server: tools (including structured output), resources, a resource template, and a prompt served per-request with no handshake and no session — the model that fits shared PHP hosting
client_negotiation.php	Dual-era negotiation from the client side: server/discover probing, legacy fallback, and the protocolMode override (auto / modern / legacy)

# stdio, auto-negotiates the modern era
php examples/client_negotiation.php examples/stateless_server.php

# force the legacy initialize handshake for comparison
php examples/client_negotiation.php examples/stateless_server.php --mode=legacy

# or over HTTP
php -S localhost:8000 examples/stateless_server.php &
php examples/client_negotiation.php http://localhost:8000

Interactive tools (elicitation / multi-round-trip input)

Example	Demonstrates
elicitation_server.php	A tool that asks the user for structured input mid-execution via an injected ElicitationContext — carried as SEP-2322 InputRequiredResult exchanges on the modern path, as server-initiated requests on the legacy path
elicitation_client.php	Registering an onElicit handler; the SDK services the multi-round-trip exchange transparently inside callTool()

php examples/elicitation_client.php   # spawns elicitation_server.php over stdio

Tasks extension (SEP-2663, io.modelcontextprotocol/tasks)

Example	Demonstrates
tasks_server.php	enableTasks() plus per-tool taskSupport: opt-in (OPTIONAL and REQUIRED), including a task that gathers in-task input
tasks_client.php	Declaring the extension, receiving a CreateTaskResult task handle from callTool(), polling tasks/get, and answering input_required via tasks/update

php examples/tasks_client.php   # spawns tasks_server.php over stdio

MCP Apps extension (SEP-1865, io.modelcontextprotocol/ui)

Example	Demonstrates
apps_server/	Linking a tool to an interactive ui:// HTML template with McpServer::ui(), rendered by Apps-capable hosts in a sandboxed iframe

HTTP clients and OAuth

Example	Demonstrates
client_http.php	A command-line HTTP client: connect options (headers, TLS, timeouts), capability inspection, and listing tools/prompts/resources
server_auth/	An OAuth 2.1-protected HTTP server (McpServer::withAuth()) with JWT validation and the RFC 9728 protected-resource metadata endpoint, deployable on cPanel/Apache

Related reference code

• ../webclient/ — a full browser-based MCP client for shared PHP hosting (OAuth flows, session resume, elicitation UI).
• ../conformance/everything-server.php and everything-client.php — the fixtures for the official MCP conformance suite; they exercise nearly every SDK surface (subscriptions, request-metadata headers, sampling, logging, OAuth grants) and are a good reference for features without a dedicated example.
• ../docs/server-dev.md and ../docs/client-dev.md — the full development guides.