Scan at scalePages with broken WebMCP tools
Pages with broken WebMCP tools
A per-URL report: one row per page that matches, over the pages a crawl reached.
What this report returns
WebMCP lets a page register tools that in-browser agents can call.
These pages register tools an agent can't use: a missing or invalid name leaves nothing an agent can call (and is rejected outright when the tool is registered imperatively), a missing description or execute handler makes it unusable, undescribed parameters can't be filled in, and duplicate names make calls ambiguous.
The Conformance Issue Detected column is true only when an imperative registerTool call omits description or execute, which the WebMCP IDL marks required; the name, duplicate-name and declarative-description rules are Lumar's profile and Chrome's guidance, and they are deliberately not spec claims because the same flag can fire on a declarative form whose rules the draft has not yet written.
An inputSchema passed as a JSON string is a defect of its own: the WebMCP dictionary member is an object (it was a string until 14 Aug 2026), so a current browser refuses the registration and the tool never exists.
How to fix it. Give every tool a valid unique name, a description, an execute handler, described parameters, and a schema object rather than JSON.stringify of one; the flagged columns show which rule each page breaks. (A missing inputSchema, as opposed to a wrongly-typed one, is informational and not a defect.)
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 Valid
webMcpValid - WebMCP Conformance Issue Detected
webMcpConformanceIssueDetected - WebMCP Findings
webMcpFindings - WebMCP Tool Names
webMcpToolNames - WebMCP Undescribed Tool Names
webMcpUndescribedToolNames - WebMCP Undescribed Param Names
webMcpUndescribedParamNames - WebMCP Tool Missing Name
webMcpToolMissingName - WebMCP Invalid Tool Name
webMcpInvalidToolName - WebMCP Tool Missing Description
webMcpToolMissingDescription - WebMCP Imperative Missing Description
webMcpImperativeMissingDescription - WebMCP Imperative Missing Execute
webMcpImperativeMissingExecute - WebMCP Input Schema Not An Object
webMcpInputSchemaNotObject - WebMCP Duplicate Tool Name
webMcpDuplicateToolName - WebMCP Imperative Missing Input Schema
webMcpImperativeMissingInputSchema - 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 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.