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

Annotations already cover readOnlyHint and openWorldHint. The description adds genuinely useful behavioral context beyond them: data can be fetched keyless via a public preview, or full results require a free Comtrade key, and country names are resolved server-side. It does not disclose rate limits or result-size behavior, so not a 5.

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 description opens with a truncated duplicate fragment ('Official UN Comtrade trade data: value and quantity by reporter country….'), then repeats the same clause in the next sentence. This redundant lead-in wastes the most valuable position and signals sloppy structure, though the remaining text is short.

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 research/retrieval tool with no output schema, the description covers source, dimensions, auth tiers, and use cases, which is reasonable. But with a nested, essentially undocumented input object, it omits how an agent should actually specify a query (which HS codes, countries, years are valid or required), leaving a real gap.

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 baseline is 3. However, the single 'input' parameter is a nested object whose schema description only points at a URL ('See https://apify.com/noniner/trade-flows') rather than documenting fields, and the description adds no parameter meaning beyond listing HS code/country/year as retrieval dimensions. It neither compensates for the opaque schema nor falls below baseline.

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 resource and scope: 'Official UN Comtrade trade data: value and quantity by reporter country, partner, product (HS code) and year.' This is clearly distinguishable from sibling data tools by naming the source and the exact dimensions available. It lacks explicit differentiation from any similarly-scoped sibling, but the trade-data specificity makes the purpose obvious.

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 trailing phrase 'For sourcing, supply-chain and market research' implies intended contexts, and the auth note ('Keyless via the public preview, or full data with a free Comtrade key') tells the agent which tier to expect. But there is no when-not guidance and no named alternative tool, leaving usage largely inferred.

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