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

Annotations already declare readOnlyHint=true and openWorldHint=true, so the safety profile is covered. The description adds nothing beyond that – no note on slug format expectations, data currency, or what a miss returns – so it contributes no behavioral context of its own.

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?

One short sentence, front-loaded with the resource and the key. Nothing is wasted, though the brevity edges toward under-specification rather than optimal conciseness.

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 one-parameter record fetch with a full output schema and read-only annotations, the minimum needed to call it correctly is present. However, it omits any hint about where valid slugs come from, which is the main practical gap for this tool family.

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 coverage is 100% and the single 'slug' parameter is documented in-schema with a concrete example ('Los-Angeles'). The description only restates that the lookup is by city_slug, adding no syntax or normalization detail beyond the schema. 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-resource pair: retrieves a Numbeo cities dataset record keyed by city_slug. The 'by city_slug' phrasing implicitly distinguishes it from the sibling search/facets tools, though it never names them 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?

No when-to-use guidance at all. It does not say to call datasets_numbeo_cities_search first to obtain a slug, nor how this differs from numbeo_cost_of_living_city or datasets_numbeo_countries_item. The agent must infer the lookup workflow.

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