WebMCP tool missing schema or description
WEBMCP-003 · v1.0
What it detects
One or more WebMCP tools registered on the page have no input schema keys and/or no description.
Why it matters
An agent relies on a tool's schema to know what parameters to pass and on its description to know when the tool applies — without either, the tool is discoverable but unusable.
How to fix
- Review the flagged tool names (in the finding's `examples`) and ensure each declares a non-empty `inputSchema` (even `{}` should be declared explicitly where the API supports it) and a clear, non-empty `description`. - Tool descriptions should state what the tool does and when it applies — an agent uses this text to decide whether to call the tool at all. - Verify: re-evaluate the page's registered WebMCP tools and confirm every tool has both a non-empty schema and a non-empty description.
References
Last reviewed: 2026-09-01 · rule v1.0