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

Annotations already declare readOnly/idempotent/closed-world, so the description's job is to add data-quality context, which it does: sums exclude confidential rows (statistical secrecy) and the result reports how many were excluded, with an instruction to mention it when citing amounts. That is meaningful behavior an agent could not get from annotations, though return shape and defaults are left to the schema/output 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?

Two dense sentences with no filler; the coverage period and units come first, followed by the confidentiality caveat. Slightly overloaded with clauses, but every element carries information.

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 7-parameter, all-optional aggregate tool with full schema coverage, an output schema and annotations, the description supplies the remaining essentials: temporal coverage, units, naming convention and the statistical-secrecy caveat. Nothing an agent needs to call or report it correctly 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 every parameter is already documented with formats, defaults and examples. The description adds only the units (millions USD, tonnes) and the names-instead-of-codes convention, which is mildly useful but does not deepen individual parameter meaning beyond the schema.

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 concrete verb+resource: foreign trade in goods since 1986, in millions of USD and tonnes, aggregated by month, year, country or category. The phrase 'con nombres en lugar de códigos' implicitly separates it from the trade_codes sibling, but no sibling is named explicitly, so routing still requires inference.

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?

Usage is only implied: the aggregation dimensions signal 'use this for grouped trade aggregates', and 'mencionalo al citar montos' gives a citation instruction. There is no explicit when-to-use/when-not guidance and no pointer to compare_series, query_sql or trade_codes for other needs.

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