# MCPmatic

> Free, in-browser tools and sourced guides for Model Context Protocol (MCP) server developers, written against MCP spec 2026-07-28. Nothing pasted into the tools is uploaded.

## Tools

- [MCP tool linter](https://mcpmatic.com/mcp-tool-linter/): checks MCP tool definitions (names, inputSchema, x-mcp-header, annotations, credential-like parameters) against spec 2026-07-28.
- [OpenAPI to MCP converter](https://mcpmatic.com/openapi-to-mcp/): converts OpenAPI 3.0/3.1 JSON into MCP tool definitions with suggested annotations.

## Guides: Start here

- [What is the Model Context Protocol (MCP)?](https://mcpmatic.com/guides/what-is-mcp/): A plain-English explanation of the Model Context Protocol: hosts, clients and servers, tools, resources and prompts, transports, and the current 2026-07-28 spec.
- [MCP vs function calling vs APIs](https://mcpmatic.com/guides/mcp-vs-function-calling/): How the Model Context Protocol relates to LLM function calling and ordinary REST APIs, with a comparison table and a practical way to decide which one you need.
- [MCP server examples](https://mcpmatic.com/guides/mcp-server-examples/): Official MCP reference servers and how to run them, minimal TypeScript and Python servers from the official quickstart, and copy-paste tool definition examples.

## Guides: Build

- [MCP tool schema reference](https://mcpmatic.com/guides/mcp-tool-schema/): Every field of an MCP tool definition: name rules, inputSchema and outputSchema, x-mcp-header, annotations, tool results, structuredContent and error handling.
- [MCP tool annotations explained](https://mcpmatic.com/guides/mcp-tool-annotations/): What readOnlyHint, destructiveHint, idempotentHint and openWorldHint mean in the Model Context Protocol, their defaults, and how to set them for common tools.
- [How to add an MCP server to Claude Desktop and Cursor](https://mcpmatic.com/guides/mcp-client-config/): Where the MCP config files live for Claude Desktop and Cursor, with copy-paste JSON for local (stdio) and remote servers and how to keep API keys out of the file.
- [How to test an MCP server](https://mcpmatic.com/guides/how-to-test-mcp-server/): Test an MCP server step by step: lint the tool list, explore it in MCP Inspector, script checks with the Inspector CLI, cover both protocol eras and run it in CI.

## Guides: Spec 2026-07-28

- [What changed in MCP spec 2026-07-28](https://mcpmatic.com/guides/mcp-2026-07-28-spec-changes/): MCP 2026-07-28 made the protocol stateless: no initialize handshake or sessions, new server/discover and multi round-trip requests, and new deprecations.
- [How to migrate an MCP server to spec 2026-07-28](https://mcpmatic.com/guides/mcp-2026-07-28-migration/): A step-by-step migration for MCP server authors moving to 2026-07-28: SDK upgrade, removing sessions, server/discover, resultType, caching, MRTR and testing.

## Guides: Security

- [MCP security best practices](https://mcpmatic.com/guides/mcp-security-best-practices/): The attacks the MCP specification warns about, from token passthrough and confused deputy to SSRF and state handle hijacking, and what servers and clients must do.
- [MCP server security checklist](https://mcpmatic.com/guides/mcp-server-security-checklist/): A practical checklist for MCP server authors based on the specification's security requirements and best practices: input validation, tokens, scopes and SSRF.

## About

- [About](https://mcpmatic.com/about/)
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