Scan at scaleSites with a broken NLWeb /mcp server
Sites with a broken NLWeb /mcp server
A site-wide report: one row per host, over the nlweb rows the crawl emitted.
What this report returns
NLWeb's MCP transport exposes the same natural-language querying as a standard MCP tool named ask.
These sites' /mcp server advertises the ask tool but agents can't use it: the tool has no description, or its inputSchema declares no usable query property.
How to fix it. Give the ask tool a description and an inputSchema with a string "query" property, per the NLWeb specification.
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 - NLWeb MCP (/mcp) Valid
nlWebMcpValid - NLWeb MCP Findings
nlWebMcpFindings - NLWeb MCP (/mcp) Ask Tool Missing Description
nlWebMcpAskToolMissingDescription - NLWeb MCP (/mcp) Ask Tool Missing Query Input
nlWebMcpAskToolMissingInputSchema
About NLWeb endpoint
Microsoft's conversational /ask route returning schema.org answers.
Read how NLWeb endpoint 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.