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

No annotations are provided, so the description carries the full behavioral burden. It usefully discloses the cost (2 credits), which is real behavioral context an agent needs. However, it says nothing about whether credits are spent on failed lookups, whether results are verified for deliverability, or what format is returned.

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 waste, with the core purpose front-loaded ahead of the cost note. Nothing redundant or padded.

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?

With no annotations and no output schema, the description should carry more: what a successful result looks like (verified address? confidence?), and how it relates to email-verify. Parameter documentation is fully covered by the schema, so the gap is in behavior and returns.

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%, so every parameter is already documented; only 'domain', 'company', 'last_name', and 'first_name' exist and the schema explains each. The description adds no parameter meaning (e.g. required vs optional combinations), so the 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 and resource: finding professional email addresses. This distinguishes it from most siblings like domains or profiles, though it never explicitly separates itself from the closely-related email-verify sibling.

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?

No guidance on when to use this versus email-verify, no prerequisites, and no stated conditions (e.g. when a lookup will fail). The only qualified guidance is the price, which is not usage guidance.

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