Does the description clearly state what the tool does and how it differs from similar tools?
The description clearly uses the verb 'Validate and normalize' and specifies 'syntax/structure only', which distinguishes this tool from sibling email verification tools like check_mx, check_spf, and detect_disposable. It also lists concrete outputs (normalized address, local-part, domain, reason on failure), leaving no ambiguity about its purpose.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.