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

The annotations already declare readOnlyHint, idempotentHint, and destructiveHint false, so the safety profile is covered. The description adds useful behavioral context: it mentions data coverage ('Covers 200+ countries, annual data') and the SDG indicator, which goes beyond the annotations. No contradiction with annotations.

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 description is two sentences with no filler. The main action and subject are front-loaded, and every sentence adds either the metric, the data source, the coverage, or the accepted input formats. It is appropriately concise for a simple read-only tool.

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 read-only, single-resource data retrieval tool, the description covers the key aspects: what is retrieved, in what units, for what scope, and the accepted input formats. The schema documents parameters and defaults, and an output schema exists, so the description does not need to explain return values. Nothing an agent needs to call this tool correctly is missing.

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%, so the parameters are fully documented in the schema. The description repeats the country code format (alpha-2, alpha-3, numeric) which is also in the schema, adding little new meaning. It doesn't further explain start_year or end_year, but those are already clear in the schema. The description provides minimal additional value beyond the schema.

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 ('Retrieve'), a specific resource ('forest area as a percentage of total land area and in hectares'), and clarifies the scope ('for any country'). It also references the data source (FAOSTAT) and the UN SDG indicator, which makes its purpose unambiguous and distinct from other environmental data tools in the sibling list.

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?

The description provides clear context about what data it retrieves and for whom ('any country'), and it explains accepted country code formats. However, it does not explicitly state when to use this tool versus alternatives or mention exclusions (e.g., 'for water stress, use faostat.environment.water_stress'). This is a minor gap given the tool's narrow purpose.

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