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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description adds genuine value beyond them by disclosing cost ("Free") and summarizing the return content, though it says nothing about rate limits or caching freshness beyond the last complete week.

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?

The usage guidance is front-loaded well, but the tail repeats the same content: "the current release ID, the last complete week, and which countries are covered" is restated as "Returns the release, its dates and per-country coverage. The live data release, the last complete week used by statistics, and coverage per country." Redundant phrasing wastes space.

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 must describe returns, and it does so (release, dates, per-country coverage). Combined with annotations, this is nearly complete; a mention of how coverage completeness is expressed would close the remaining gap.

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?

With 100% schema coverage, the schema already documents the ISO-2 format and the omit-for-all behavior. The description's "Pass a country (ISO-2) for one country" restates the schema rather than adding new semantics, so 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?

The description states a specific verb and resource: check what data is live (release ID, last complete week, per-country coverage). It is clearly distinguishable from the sibling lookup/utility tools, and an agent can tell what it returns without opening the schema.

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?

"Use to check what data is live before quoting figures" gives a clear triggering context and implies a when-not (don't quote without checking). No sibling alternatives are named, but the usage scenario is unambiguous.

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