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

Annotations already declare readOnlyHint=true and openWorldHint=true, so safety and external-data sourcing are covered structurally. The description adds nothing further — no indication of data currency, geographic coverage, or whether the slug must match Numbeo's canonical form.

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 phrase with no wasted words, but it is under-specified rather than genuinely concise — there is no front-loaded statement of what the call returns or requires.

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 only one required parameter and an output schema present, the structured fields do most of the work, but the description still omits what price categories come back and how it differs from the country/indices siblings. For a lookup tool in a dense Numbeo cluster, that routing information is the missing piece.

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% and the single 'slug' parameter includes an example ('Los-Angeles'), so the schema carries the burden. The description adds no extra syntax or format guidance, which is the baseline-3 case.

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 phrase names the resource (Numbeo city cost-of-living prices) but contains no verb and no scope qualifier, so the agent must infer it returns a price breakdown for one city. Several siblings exist (numbeo_cost_of_living_country, numbeo_indices_city, numbeo_cost_of_living_rankings) and the description does nothing to distinguish this one from them.

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, no mention of when to prefer the country, indices, or rankings siblings. The only implicit cue is the word 'city' in the name, which the description merely repeats.

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