WebMCP schema validity

A valid schema ensures that the AI agent understands the structure of the data it needs to provide.

How the WebMCP schema validity audit fails

The audit fails if:

  • A form has a tooldescription but is missing the toolname attribute.
  • A form has a toolname but is missing the tooldescription attribute.
  • A required form field is missing a name attribute.

Lighthouse also issues a warning if an optional field has a name but is missing a toolparamdescription or an associated <label>.

How to fix

  1. Ensure symmetry: Always provide both a name and a description for every tool.
  2. Add names to inputs: Verify that every input element within a tool form has a unique name attribute.
  3. Provide parameter context: Add toolparamdescription to inputs to help the agent understand what value is expected.