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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so safety is covered. The description adds real behavioral context beyond that: licensing/public-domain status per source, update frequency (daily vs monthly), and that each row carries its own source and frequency.

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?

Front-loaded with the core purpose and then the two source families and their change metrics in a compact form. Slightly dense with enumerated commodity names, but every clause carries distinguishing information rather than 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?

With no output schema and no parameters, the description must convey the return shape, and it does: two source families, the metrics attached (7/30-day changes, month-on-month), and per-row source and frequency fields. An agent knows what it will get.

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?

The tool takes zero parameters, so the baseline is 4. There is no parameter semantics to clarify, and the description correctly spends its words on what the (parameterless) call returns instead.

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 (benchmark prices) and precise resources: U.S. EIA daily spot for Brent/WTI/Henry Hub and World Bank Pink Sheet monthly averages for gas, wheat, maize, urea. The sourcing detail makes it unmistakably distinct from the sanctions, risk, and corridor siblings.

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?

There is no explicit when-to-use statement, no prerequisites, and no named alternative among siblings. Usage is only implied by the data content (benchmark commodity pricing), which an agent can infer but must guess at.

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