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

Annotations declare readOnlyHint=true, openWorldHint=true, idempotentHint=true, destructiveHint=false, so the safety profile is covered. The description adds that the data is 'Keyless, official World Bank data,' which is useful context about authentication (none required) and source authority. However, it doesn't describe return format (e.g., list of year-value pairs), pagination, rate limits, or how missing data is handled. With annotations handling the core behavior, a 3 is appropriate.

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 sentences, front-loaded with the core purpose, followed by helpful examples. No filler or repetition. Efficient and well-structured, though it could be slightly more concise by omitting some redundancy (e.g., the country examples).

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 tool with full annotation coverage and 100% schema description, the description is adequate but not complete. It doesn't mention that there is no output schema and doesn't describe the return structure (e.g., a time series of values). It also doesn't clarify default behavior (e.g., default country 'US' and full year range if no start/end specified). Missing these details leaves some ambiguity for an agent.

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 all four parameters. The description adds marginal value by listing friendly indicator names and country code formats, but these are also present in the schema descriptions (e.g., the schema lists the same friendly indicators and mentions ISO2/ISO3 codes). The description does mention 'WLD' for world in the schema but not in the description; however, the description provides no additional parameter semantics beyond what the schema offers. Baseline 3 is correct.

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+resource: 'Time series for a World Bank development indicator for one country.' Names the data source (official World Bank) and the output type (time series). This clearly distinguishes it from siblings worldbank_compare (multi-country) and worldbank_country_profile (broader profile).

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 implies usage through examples ('Friendly indicators: ...', 'Country accepts ISO2/ISO3 codes or common names'), which helps an agent know it can pass friendly names. However, it doesn't explicitly say when to use this tool vs. worldbank_compare or worldbank_country_profile. No exclusions or alternatives are named.

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