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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), yet the description adds genuinely non-obvious semantics: thin-ingestion domains (votes, interventions) are omitted from both `domains` and `domains_health` while their endpoints still serve data; `domains` means 'ever had data', not 'current'; and `domains_health` is guaranteed to agree with get_health/get_country_health. These are exactly the behavioral caveats an agent cannot infer on 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?

Three tight paragraphs: purpose first, then a usage directive, then field semantics. The final clause ('computed the exact same way as get_health/get_country_health — the two are guaranteed to agree') states the same fact twice, a small redundancy in an otherwise waste-free definition.

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 shape needn't be explained, but the description still names the two key fields (`domains`, `domains_health`) and their differing meaning — the exact distinction an agent needs before deciding whether to trust the coverage map. Complete for a zero-parameter lookup tool.

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 takes zero parameters and the description correctly spends no space on argument semantics. Baseline is 4 for a no-argument tool.

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 resource and scope: a reference catalog of the 12 LATAM countries plus per-country domain coverage (regulations, consultations, bills, actors, schedules, news, transcripts). This clearly distinguishes it from the sibling data-fetching tools like list_regulations or get_country_health, which return actual records rather than a coverage map.

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?

Explicitly says 'Call this first when unsure whether a country or domain is covered before querying it' — a concrete when-to-use rule. It also names the alternative for a related question (use `domains_health` for freshness) and ties that signal to get_health/get_country_health, leaving nothing to inference.

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