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

Read-only safety is already covered by readOnlyHint, but the description adds meaningful behavior: only finalized issued invoices are included, received invoices are broken out by VAT rate, and output rows include base, VAT, IRPF/deductible quota, total, and period sums. It does not discuss pagination or auth, but for a simple report it discloses the important semantics.

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 is front-loaded and dense with useful information, with no filler. It moves from what the report is to what each row contains to how it relates to the gestoría export and its non-advice nature.

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 does a good job explaining the return shape and line granularity. It is nearly complete for a two-parameter read-only report, though it could be more explicit about the year parameter and whether all received invoices are included.

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 coverage is 50%: quarter is documented in the schema, while year is not. The description reinforces that the report covers a quarter or year, but it does not add year format/range details or explain requiredness beyond what the schema already shows.

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?

The description states a specific resource and scope: libro registro of issued and received invoices for a quarter or year, with one line per invoice and VAT rate. It also distinguishes this listing from export/advice behavior by saying it contains the same rows as the gestoría export and is a pure listing with no advice.

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 implied by the scope ('for a quarter or year') and by 'Pure listing, no advice,' but the description does not explicitly say when to use this instead of siblings such as list_invoices or gestoria_export. It gives context without clear alternatives or exclusions.

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