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 expectations are covered. The description adds only that results include per-city index values alongside prices, which is mildly useful but thin behavioral context for a read tool with no other traits disclosed.

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 with no filler, which is appropriate for a one-parameter read tool. It is efficient though slightly under-specified rather than padded.

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?

An output schema exists, so return values need not be explained, and the input surface is one well-documented parameter. What is missing is disambiguation from the cluster of near-identical numbeo cost-of-living and indices siblings, which is the main risk this description should have addressed.

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 'country' parameter already documents the expected spelling ('Country name as Numbeo spells it, e.g. Vietnam'). The description adds no additional parameter meaning, so the 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 resource (country cost-of-living prices) and a scope (country-level, with a by-city index table), so the verb/resource pairing is discernible. However, it never distinguishes itself from the very similar siblings numbeo_cost_of_living_city or numbeo_indices_country, and 'prices and by-city index table' is loose about what the tool actually returns. Adequate but not crisp.

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?

There is no when-to-use guidance at all — nothing tells the agent to pick this over numbeo_cost_of_living_city for a city lookup or numbeo_indices_country for index-only data. The description merely labels the content, leaving selection to inference from the tool name alone.

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