faostat_get_datasize

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

With no annotations, the description carries the full burden, and it does disclose the key traits: the result is an estimate (approximate), it happens 'BEFORE fetching' (cheap, non-retrieving), and it mirrors the filters of the data tool. It stops short of stating accuracy, cost, or any caveats about the estimate, so it is not fully transparent, but the essential behavioral profile is present.

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 sentences, front-loaded with the outcome, then the usage trigger, then the parameter relationship. No filler or repetition; every clause carries information.

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 pre-fetch purpose is clear. But with 10 undocumented parameters at 0% schema coverage, an agent still lacks the field-level detail needed to construct a valid query beyond the pointer to faostat_get_data.

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 0% across 10 parameters, so the description must compensate; it partially does by asserting 'Accepts the same filter parameters as faostat_get_data', which lets an agent borrow that tool's semantics. However, it adds no per-parameter meaning (e.g., the area vs area_cs distinction, domain_code requirement) on its own.

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 verb and resource ('Estimate the number of rows a data query will return') and explicitly distinguishes itself from the sibling faostat_get_data by framing itself as a pre-fetch check. An agent can tell exactly what this tool produces 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?

Gives an explicit trigger ('Use this to check if a query is too large before calling faostat_get_data') and names the alternative it precedes. The when-to-use condition and the routing decision are both spelled out rather than inferred.

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