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

Annotations already declare readOnlyHint=true, non-destructive, closed-world, so the safety profile is covered. The description adds real context beyond that: newest-first ordering and the exact fields returned (check_id, status, counts, credited_cents), plus the fact that detail requires a second call. It does not mention the 50-item cap or what 'counts' aggregates mean, which limits how much behavioral insight it provides.

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 compact sentence front-loads the resource and ordering, then enumerates return fields and the follow-up tool. Every clause carries information; there is no filler.

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 output schema, the description compensates by naming the returned fields, and it explains how to get detail via get_email_check. The main residual gap is that it does not signal the hard 50-item cap or that there is no cursor-based pagination, which matters for an agent walking a long history.

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%, with both limit (min 1, max 50, default 20) and passport_token fully documented in the schema. The description adds no parameter guidance — no hint about the maximum page size or when the passport_token fallback matters — 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?

The description identifies the resource (the caller's owner's email checks), the sort order (newest first), and the returned fields, which is enough for an agent to distinguish it from check_emails (which presumably runs a check) and get_email_check (which returns results). It stops short of an explicit verb, relying on the ordering/field enumeration to imply a listing, so it is clear but slightly shy of a full verb+resource statement.

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 explicitly routes the agent to get_email_check 'for the results', which is a concrete alternative-tool condition. It does not state when not to use it (e.g., per-mailbox filtering or full history via other tooling), so the exclusion set is implied rather than declared.

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