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

Annotations already declare readOnly, idempotent, non-destructive, open-world. Beyond that, the description discloses the default current-row-per-order-number behavior, what history=true adds, the authority hierarchy versus TARIC, and that access is free — genuine context an agent would otherwise lack. Pagination semantics are left to the schema.

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 source, then returned fields, then default behavior, then sourcing caveat. Information-dense with little waste; the single-word 'Free.' is terse but earns its place as a cost signal.

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, the description carries the return-value burden and does so by enumerating the row fields (order number, category, CN codes, country, volumes, out-of-quota duty, act). Safety is covered by annotations. Only filter-combination behavior is left unaddressed, which is a minor residual 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. The description adds modest meaning — units (tonnes per period), the 'other countries' residual grouping, and the history default — but no syntax or interaction rules for combining the four optional filters, so it does not exceed the schema meaningfully.

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 (EU tariff quotas), its source (the Official Journal act's own tables), and the two regimes covered (steel country quotas, safeguard quotas like ferro-alloys). It enumerates the returned fields, so an agent knows exactly what it gets. It does not explicitly name the nearest sibling, eu_trade_defence_measures, so the boundary with that tool must be inferred.

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?

"Quota balances are in TARIC; the Official Journal is authoritative" effectively excludes balance-lookup use cases, and the default/history behavior is spelled out. But there is no explicit statement of when to call this versus eu_trade_defence_measures or how filters (cn, country, celex) combine. Usage is implied rather than directed.

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