Readable is not yet usable
Clear pages and metadata help an agent understand a business. Callable readiness requires an explicit interface such as OpenAPI or MCP only when the business actually offers an operation an agent should invoke.
Applicability prevents false failures
A publisher may need strong crawlability and structured identity but no API. A paid API provider needs much more: typed operations, access rules, error models, idempotency, and pricing scoped to the resource.
Trust closes the loop
HTTPS, support, limitations, stable errors, terms, performance, and accessible content make machine-readable claims more dependable. Readiness is not a certification; it is a traceable assessment of observed public evidence.