Ventas de combustibles de ANCAP

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

Annotations already declare readOnly/idempotent/openWorld, so safety is covered; the description adds real value with output-shape behavior (product list + missing months vs. monthly series) and a comparability caveat about not comparing years with different month counts. It does not cover auth, rate limits, or pagination, 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?

Front-loaded with purpose then per-parameter and per-mode details; dense but nearly every clause carries information. Slightly heavy with parentheticals and the units note tacked on at the end, but no 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?

Given an output schema exists, the description still supplies the things the schema cannot: the two behavioral modes, mercado vocabulary, date format, and unit caveat (miles de m3 except petcoke in tonnes). An agent has everything needed to call it correctly.

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 0%, so the description carries the full burden and does so: it defines `linea`'s toggle semantics, enumerates `mercado` values (vacio = todos), and specifies `desde`/`hasta` as AAAA-MM format.

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+resource: quantity sold by ANCAP of each fuel, per month, explicitly scoped as volumes not prices. It also names the sibling to use for prices (combustible_ancap), so an agent can distinguish it from that tool immediately.

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?

Explicitly splits behavior: without `linea` you get the product catalog plus unpublished months, with `linea` you get the monthly series and yearly totals. It also gives an explicit when-not (prices → combustible_ancap) and enumerates mercado values.

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