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

Annotations already declare readOnly/idempotent/openWorld/non-destructive, and the description goes well beyond them by disclosing the payment requirement ($0.01 USDC per successful call via x402 on Solana) and an alternate HTTPS transport. Cost and payment-auth details are exactly the kind of operational context an agent needs before invoking, and it is stated unambiguously.

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 resource and indicator list, then limits, then price and transport — a logical order with little filler. The indicator enumeration partially duplicates the schema's enum list, which is the only real 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 lookup tool with a fully documented schema and no output schema, the description supplies source semantics (actuals vs projections), caps, and cost. It could still say more about the returned shape (e.g., how the two sources are aligned 'side by side'), but nothing essential to calling it is missing.

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 all five parameters (country, indicators, from, to, source) are already documented in the schema. The description restates the 10-country and 8-indicator caps but adds no syntax, format, or edge-case guidance beyond that, 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?

Names a specific resource (macro indicators) with an explicit scope — by country and year — and enumerates the exact indicator families and the two underlying sources (World Bank WDI actuals vs IMF WEO projections). An agent can distinguish this from siblings like us_macro or treasury_rates based on the multi-country, dual-source framing.

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 conveys what data it returns and the operational limits (up to 10 countries, 8 indicators per call), which implies usage, but never states when to choose it over the sibling us_macro (US-only) or fx_rate. No explicit when-not conditions or alternative routing are given.

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