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

Annotations already declare read-only, idempotent, open-world, and non-destructive behavior, so the description adds meaningful payment and auth context: first 3 calls free, X-WALLET header requirement, no charge on upstream failure, and USDC cost. It also names returned fields, but does not cover pagination or broader rate limits.

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 purpose is front-loaded, and payment details are essential for invocation. However, the sentence about autonomous agents, A2A, ESG, and benchmarking pipelines is promotional filler that does not help an agent decide or call the tool, making the description longer than necessary for a one-parameter API.

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 simple paid read-only API with no output schema, the description summarizes the returned fields and essential payment/auth behavior, making it largely complete. It still omits response shape and pagination behavior, but those gaps are relatively minor given the tool's simplicity.

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 coverage is 100% and the schema itself provides an example JSON input with indicatorCode, $filter, and $top. The description names an indicator example and the dimensions of the timeseries, but adds little syntax or constraint detail beyond what the schema already provides for the single generic input parameter.

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: returns WHO Global Health Observatory OData time series for an indicator, with example indicator code. It also names the endpoint and returned dimensions, clearly distinguishing it from the unrelated sibling tools.

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?

Describes intended users and use cases (autonomous agents, ESG, country benchmarking) and the query surface (indicator + country to yearly values), implying when the tool is useful. However, it does not explicitly say when to choose it over alternatives or when not to use it.

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