Scan at scalePages with undescribed WebMCP tools
Pages with undescribed WebMCP tools
A per-URL report: one row per page that matches, over the pages a crawl reached.
What this report returns
An agent decides whether and how to call a WebMCP tool from its descriptions; an undescribed tool or parameter forces it to guess or skip the tool entirely.
A row appears here when any of these is wrong, worst first:
- Tool Missing DescriptionA declarative form tool has no tooldescription, which Chrome's declarative API expects (the W3C draft no longer specifies the declarative form), so an agent can't know what the tool does.Fix Add a tooldescription attribute saying what the tool does and when to use it.
- Imperative Missing DescriptionA
registerToolcall has no (or an empty) description, which is required, so agents can't tell what the tool does.Fix Pass a description saying what it does and when to call it. - Param Missing DescriptionA tool parameter has no usable description (no toolparamdescription, associated label, or aria-description), so agents can't supply it correctly.Fix Describe every parameter, e.g.
toolparamdescription="Departure date, YYYY-MM-DD".
The Conformance Issue Detected column separates the two cases: it is true only for the imperative call, where the W3C WebMCP draft requires a description, and false when the gap is on a declarative form or a parameter, which is Chrome's guidance and Lumar's readiness bar rather than a spec rule.
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.
- WebMCP Conformance Issue Detected
webMcpConformanceIssueDetected - WebMCP Findings
webMcpFindings - WebMCP Undescribed Tool Names
webMcpUndescribedToolNames - WebMCP Undescribed Parameters
webMcpUndescribedParamNames - WebMCP Tool Missing Description
webMcpToolMissingDescription - WebMCP Imperative Missing Description
webMcpImperativeMissingDescription - WebMCP Param Missing Description
webMcpParamMissingDescription
About WebMCP
In-page tools a browsing agent can call directly.
Read how WebMCP is checked, including the specification it is validated against and a worked correct and broken example.
Running it
This report comes with Agentic Readiness in Lumar and appears on every crawl of any project that has it turned on. See the whole set, or check a single URL with the scanner on this site, which runs the same code with no account.