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

readOnlyHint=true already establishes this is a safe read, so the description's job is to add context beyond that. It usefully discloses that results carry ids and that the atlas is hierarchical, but it says nothing about result volume (a world-level or city-level query could be enormous) or pagination, which is a meaningful omission for an enumeration tool with no output 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 short sentences, front-loaded with what the resource is before the filtering advice; no filler or restated boilerplate. The 'The atlas:' opener is slightly elliptical but still carries real information about scope and ids.

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 zero-required-parameter, read-only lookup with no output schema, the description covers what the resource contains, the id payload, and the two main filters. It stops short of describing result size, ordering, or how the hierarchy levels relate, which an agent would want before calling an unfiltered list.

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 only 33% — 'parent' has no schema description at all and 'kind' is documented only by its enum. The description compensates by explaining parent as a parent id with a concrete 'us' example and by enumerating the kinds inline. Only 'name' goes unelaborated, and that one is already described in the schema.

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 names the resource precisely — a geographic atlas spanning world, country, state, county and city levels — and states that each entry carries an id. It does not use an explicit verb like 'list' (the name and title supply that) and the sibling tools are unrelated, so differentiation is less of an issue than internal clarity, which is good.

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 gives concrete filtering guidance ('filter by parent id ... or kind'), including a worked example of 'us' returning US states, which implies hierarchical drill-down usage. However, it never states when to use this versus other lookup tools, whether filters combine, or what happens with no filter at all.

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