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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered; the description goes beyond them by defining how 'frequency' is computed (articles, publications, references) and warning that country filtering surfaces cross-border mentions. It does not disclose what a result entry contains or how paging interacts with the frequency ranking.

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?

Purpose and sort order are front-loaded in the first clause, which is correct. The second sentence is heavily nested (parentheticals, em-dashes, semicolons) and could be split, but every element carries information rather than 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 should say more about the returned entry shape; it explains ordering and frequency but not what fields a person record exposes. For a 3-parameter read-only list with full annotation coverage, the remaining gap is modest but real.

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?

At 67% schema coverage, the description adds net-new meaning for 'country' — the consequence of mention-based selection and the Nigeria edge case — rather than merely restating the schema. The frequency-ranking explanation also implicitly justifies limit/offset ordering, though 'offset' is never addressed in either place.

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 personnes from the IWAC index') plus the ordering ('sorted by frequency, most-referenced first'), which an agent can distinguish from siblings like list_locations or search_index. It never explicitly names a sibling to contrast against, so differentiation is inferential rather than stated.

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 description spends its guidance budget on one thing: how the 'country' filter behaves (mentioned-in, not located-in) and the resulting caveat that foreign/cross-border entries appear and Nigeria yields few results. That is genuine usage guidance for that parameter, but there is no guidance on when to choose this over search_index, get_index_entry, list_locations, or how to page through results.

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