Modern protocol first
The inspector starts with the 2026-07-28 stateless request model and server/discover instead of treating the removed initialize handshake as the latest protocol.
MCP Protocol Diagnostic Tool
MCP Inspector: Test MCP Server Protocol, Tools and Compatibility
Enter a public MCP HTTP/HTTPS endpoint. The inspector tries the 2026-07-28 stateless server/discover flow first, then recognizes 2025-era initialize compatibility when needed. Every result includes reviewable evidence, and the public version never executes a tool.
2026-07-28 firstLegacy compatibilitytools/resources/prompts listNo tools/callSSRF protectionNo login
Tool
Inspection Boundary
Inspect compatibility without causing side effects
Legacy still recognized
If modern negotiation fails, it can identify the 2025-era initialize/initialized lifecycle so valid compatibility is not reported as a generic failure.
Public read-only scope
Only capabilities and first-page catalogs are read. No tool is invoked, no credentials are accepted, and private/reserved networks or non-standard ports are rejected.
FAQ
Frequently asked questions
Does MCP Inspector execute any server tools?
No. The public inspector only sends discovery, protocol negotiation, and first-page list requests. It never sends tools/call or invokes a server tool.
Why does it probe server/discover before initialize?
MCP 2026-07-28 introduced the modern stateless era and removed the initialize/initialized handshake. server/discover is the modern capability discovery path. The inspector still recognizes 2025-era initialize compatibility when modern negotiation is unavailable.
Can I paste an MCP token or Authorization header?
No. The public inspector does not accept, store, or forward tokens, cookies, API keys, or Authorization. Protected endpoints are limited to public auth-boundary detection; deeper auth validation belongs in an authorized local or development environment.
Is the MCP Conformance Score an official certification?
No. It is an XBSTACK engineering assessment of observable protocol behavior. It helps diagnose compatibility and implementation gaps but is not an official MCP or SDK certification.
