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

Annotations already establish readOnlyHint=true, idempotentHint=true, and destructiveHint=false, covering the safety profile. The description adds useful behavioral constraints — it returns the 'most recent value' (not a time series) and caps input at 'up to 6' countries — but it does not disclose what happens with invalid country codes, missing data, or how results are formatted and ordered.

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?

Two sentences, each earning its place: the first states the purpose and the 6-country cap, the second states the required input format. The purpose is front-loaded and there is no filler or redundancy.

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, two-parameter tool with 100% schema coverage and safety annotations, the description is nearly sufficient. The only meaningful gap is the absence of any mention of the return shape or error behavior (e.g., invalid country codes, unavailable indicator data), which matters because there is no output schema to cover that.

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 both countries and indicator are already documented in the schema with the enumerated indicator list. The description adds the 'up to 6' limit and the comma-separated format for countries, but adds no meaning for the indicator parameter beyond what the schema provides, so the baseline 3 applies.

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 uses a specific verb ('Compare') plus a clear resource ('a World Bank indicator') and scope ('across multiple countries (up to 6)'). This cleanly distinguishes it from sibling tools like worldbank_indicator and worldbank_country_profile without requiring schema inspection.

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 its use case — comparing a single indicator's most recent value across several countries — but never explicitly names alternatives or exclusions. It does not tell the agent to use worldbank_indicator for single-country or historical data, nor worldbank_country_profile for a country dossier, so routing guidance is left to inference.

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