Scan at scaleSites with a broken MCP server card
Sites with a broken MCP server card
A site-wide report: one row per host, over the mcp_server rows the crawl emitted.
What this report returns
An MCP server card advertises a site's Model Context Protocol server so agents can discover and connect to it.
These sites publish a card agents can't connect from: invalid JSON, no absolute http(s) endpoint URL, or an endpoint that answers an MCP handshake with an ordinary web response instead of JSON-RPC.
How to fix it. Serve valid JSON declaring the server's full endpoint, e.g. { "url": "https://mcp.example.com/mcp", "transport": "streamable-http" }, and make sure that URL is a live MCP server rather than a static document. Note the card format is an experimental MCP extension (SEP-2127), which reserves the card at <your-mcp-url>/server-card and lists a /.well-known location among its alternatives considered as not recommended; we probe /.well-known/mcp.json and /.well-known/mcp-server-card.json because sites in the wild use them, so a card found there is real adoption at a permitted but non-recommended path.
(A missing transport is shown for context but is informational.)
The columns it shows
Every defect this technology can carry is a column in the grid, worst first, so nothing is hidden behind a filter you have to know to apply.
- Host
host - MCP Server Valid
mcpServerValid - MCP Server Conformance Issue Detected
mcpServerConformanceIssueDetected - MCP Server Findings
mcpServerFindings - MCP Server Endpoint URL
mcpServerEndpointUrl - MCP Server Transports
mcpServerTransports - MCP Server Tool Names
mcpServerToolNames - MCP Server Invalid JSON
mcpServerInvalidJson - MCP Server Missing URL
mcpServerMissingUrl - MCP Server Endpoint Not MCP
mcpServerEndpointNotMcp - MCP Server Endpoint Unavailable
mcpServerEndpointUnavailable - MCP Server Tool Missing Name
mcpServerToolMissingName - MCP Server Tool Missing Input Schema
mcpServerToolMissingInputSchema - MCP Server Duplicate Tool Name
mcpServerDuplicateToolName - MCP Server Tool Missing Description
mcpServerToolMissingDescription - MCP Server Unknown Method Accepted
mcpServerUnknownMethodAccepted - MCP Server Missing Transport
mcpServerMissingTransport - MCP Server Stale Endpoint
mcpServerStaleEndpoint - MCP Server Partially Assessed
mcpServerPartiallyAssessed
About MCP server card
Advertises a Model Context Protocol endpoint agents can call.
Read how MCP server card is checked, including the specification it is validated against and a worked correct and broken example.
Running it
This report ships in the Lumar agent-readiness container and appears on any project it is linked to, on every crawl. See the whole set, or check a single URL with the scanner on this site, which runs the same code with no account.