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

With readOnlyHint=true already declared, the description still adds real value: it discloses pagination ('one page at a time') and flags that results contain personal data, advising minimal fetching. It stops short of describing rate limits or result shape, but the cursor/limit mechanics are covered in the schema.

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 sentences, zero waste: purpose and filter surface first, then the pagination/privacy constraint. 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 an 8-parameter read-only listing tool with full schema coverage and no output schema, the description covers purpose, filtering and the sensitive-data caveat. Only sibling routing and output expectations are thin, and the former is a minor gap given the clear plural/paginated framing.

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 the schema already explains every parameter including cursor continuation and page-size truncation. The description names three of the filters (state, search, label) but adds no syntax or behavioral detail beyond what the schema states; 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 — 'List the members (subscribers) of a mailing list' — plus the paginated nature of the call. The plural 'members' and pagination framing implicitly separate it from the singular laposta_get_member, but no sibling is named explicitly.

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?

The filtering dimensions (state, search, label) and the page-by-page usage are stated, and 'only fetch what the task needs' gives a usage constraint. However, it never says when to prefer this over laposta_get_member or laposta_list_segments when only one member or a segment view is needed.

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