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

With no annotations provided, the description carries the full burden of behavioral disclosure. It usefully discloses that the tool returns 'latest available value each' rather than a time series, which is a meaningful behavioral trait. It could add details about output shape or handling of missing data, but the core behavior is transparent.

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 one sentence, front-loads the primary action and scope, and then adds the use case. Every word earns its place; there is no redundant or vague filler.

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 two-parameter tool with 100% schema coverage, the description is nearly complete. It does not describe return format or missing-data behavior, which could matter given there is no output schema, but the core selection semantics and use case are sufficiently clear for an agent to call it correctly.

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 schema already documents both parameters clearly. The description adds only the 'latest available value each' nuance and ranking/benchmarking intent, which is useful but not a substantial lift beyond the schema. Baseline 3 is appropriate.

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 ('Compare'), a precise resource ('one indicator across several countries'), and a key constraint ('latest available value each'). This clearly distinguishes it from siblings like country_indicator, which presumably handles a single country, and us_series, which presumably handles US time series.

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 phrase 'Good for ranking or benchmarking economies' gives a clear, practical use case for when to select this tool. It does not explicitly name alternative tools or exclusion conditions, but the intended context is evident and not misleading.

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