Verify email addresses

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations only indicate non-read-only (false) and non-destructive (false). Description adds critical context: wallet deduction, per-address billing, required scope, and specific checks. This is valuable beyond annotations.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences each add unique value: billing, checks, scope. No redundancy, fully front-loaded with the most critical info first.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Explains what the tool does and its side effects, but does not describe the return value or output format. Since no output schema exists, the agent lacks information on what the tool returns, which is a notable gap.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema describes 'emails' as an array with format email. Description enriches by explaining the purpose of the checks performed on these addresses, going beyond the schema's minimal 'One or more email addresses.'

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Clearly states verb 'Checks' and resource 'email addresses for deliverability', listing specific checks (syntax, MX, mailbox, disposable, role-account). Distinct from all sibling tools which handle SMS, voice, USSD, webhooks, etc.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Implies usage for verifying email deliverability and notes billing, but does not explicitly advise when to use or not use, nor mention alternatives. No direct alternative exists among siblings, but guidance is minimal.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.