verify_emailsVerify up to 50 email addresses at once and get a deliverability verdict for each, synchronously. Consumes 1 credit per address. For larger lists (up to 1000), use verify_list.
| Name | Required | Description | Default |
|---|---|---|---|
| emails | Yes | Email addresses to verify (1-50). |
Changes observed during successful MCP inspections.
Input schema / properties / emails / descriptionPrevious value: -"Email addresses to verify (1–50)."New value: +"Email addresses to verify (1-50)."Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, openWorldHint=true, destructiveHint=false. The description adds two things annotations cannot carry: the call is synchronous, and it consumes 1 credit per address. No mention of what happens on partial failure or whether invalid addresses consume credits.
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?
Two short sentences, zero filler. Scope and the alternative routing are front-loaded before any detail.
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?
Covers limit, synchronous behavior, credit cost, escalation path, and the nature of the return value ('deliverability verdict for each') despite no output schema. Nothing an agent needs to call this correctly is missing.
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 description coverage is 100% and the single parameter is fully documented with its 1-50 range, matching the description's 'up to 50'. The description adds no syntax or format guidance (e.g. duplicates, malformed input handling), so baseline 3 applies.
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?
States a specific verb ('verify'), the resource ('email addresses'), the batch cap (50), and the synchronous verdict output in one sentence. It is immediately distinguishable from verify_list by scope.
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?
Explicitly routes bulk work to verify_list with the threshold ('larger lists (up to 1000)'). It does not mention the single-address sibling verify_email, so the boundary on the small end is left implicit.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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