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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the safety profile is carried by structured data. The description adds real value beyond that by explaining the semantics of the is_default flag (marks the locale used when none is picked), which enriches the agent's understanding of the returned data. No contradiction with annotations.

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 that leads with the core purpose, then appends the one piece of behavioral detail (is_default) that matters. Zero filler words; 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?

There is no output schema, so the description carries the burden of explaining the return shape, and it does: it defines locales and the is_default field's meaning. For a 0-parameter read-only list tool this is complete; only a slightly richer return-format description would push it higher.

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?

The tool has zero parameters, so the baseline of 4 applies per the rubric. Nothing is needed here; the description instead focuses attention on the meaningful part of the call: interpreting the returned locale objects and the is_default field.

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?

Description states a specific verb (List) plus a precise resource (career site locales) with examples, and clarifies the domain use (accepted by language parameters). It naturally distinguishes from siblings like hires_get_career_site_settings and hires_list_career_jobs by naming exactly what is enumerated.

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 phrase 'accepted by language parameters' makes the use case clear: call this to obtain valid locale values for language parameters elsewhere. It doesn't explicitly name alternatives or state when-not-to-use, but the context is unambiguous and no sibling serves the identical purpose.

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