verify_email

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

The description discloses two important non-obvious behaviors beyond the annotations: the operation is asynchronous and requires polling, and it works on catch-all domains. This is substantial added context with no contradiction to the 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?

The description is two tight sentences with no filler. The purpose is front-loaded, and the async polling detail is placed immediately after, making it easy for an agent to parse.

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?

For a single-parameter async tool, the description is nearly complete: it states what the tool does, its catch-all support, and the next step in the workflow. It could mention polling timing or potential failure behavior, but the referenced sibling tool likely covers the result details.

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 email parameter is already well documented as 'Email address to verify'. The description adds no additional parameter-level detail, so the baseline score of 3 is appropriate.

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?

The description states a specific verb ('Verify'), a specific resource ('email address'), and the precise goal ('deliverable'). It also adds a distinguishing capability ('Works on catch-all domains') that helps separate it from lookup-style siblings like find_email.

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?

It clearly explains the required asynchronous workflow: returns a verification id, then poll get_verification_result. However, it does not explicitly state when to prefer this over the bulk variant verify_emails_bulk or the find_email sibling.

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