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

Annotations already declare a read-only, non-destructive, closed-world operation, so the safety profile is covered. The description adds value beyond that by disclosing the sort order ('newest first') and the exact return fields (check_id, domain, status, score, counts), which is meaningful given there is no output schema. It does not mention pagination behavior beyond the schema's limit parameter.

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?

A single front-loaded sentence packs scope, ordering, returned fields, and a sibling pointer with no filler. Every clause earns its place.

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 simple read-only list with fully described parameters, the description covers ordering, returned fields, and where to get detail. It leaves minor things implicit, such as what 'owner' scope concretely means and behavior when no checks exist, but nothing essential for calling it 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 coverage is 100%, with both limit and passport_token documented in the schema itself. The description adds no additional parameter meaning (no default, maximum, or auth context beyond what the schema says), so the baseline 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 clearly states it returns the owner's sender checks, with ordering ('newest first') and the fields returned. It implicitly names the action ('sender checks') and routes detail work to get_sender_check. It does not explicitly distinguish itself from other list-style siblings such as check_sender or list_email_checks, which keeps it below a 5.

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 points to get_sender_check when the detailed report is needed, giving a usable alternative and condition. It stops short of stating explicit exclusions or when not to use this list (e.g., versus check_sender), so it is clear context rather than complete guidance.

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