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How to Test MCP Servers: A Complete Guide for 2026
By NexaMarTech Team7 min read
Learn how to validate Model Context Protocol servers end-to-end — from handshake to tool invocation — with a free browser-based tester.
How to Test MCP Servers: A Complete Guide
Model Context Protocol (MCP) is quickly becoming the USB-C of AI agents. But before you ship an MCP server to production, you need to know it actually works with clients like ChatGPT, Claude, and Cursor.
What to test
- Initialize handshake — protocol version negotiation
- tools/list — schema validity and descriptions
- tools/call — real invocations with expected shapes
- Auth — OAuth 2.1 or bearer tokens
- Error handling — malformed requests should not 500
Using the NexaMarTech MCP Tester
Head to /tools/mcp-tester, paste your server URL, and click Test. The tool runs the full JSON-RPC sequence and reports each step.
Common failures
- Missing CORS headers on the SSE endpoint
- Returning tool results outside the
contentarray - Forgetting to advertise
serverInfo.version
Ship with confidence — test first.
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