reports_vat_oss

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

Annotations already declare readOnly/idempotent/non-destructive, so the description is free to add the genuinely useful behavior: conversion at the ECB rate of the last day of the quarter (D398 rule), the null EUR amounts while the quarter is running, and the RO/<vatCode>/Q<n>.<year> reference format. It does not cover authorization requirements or what happens for non-OSS companies, which is the remaining gap.

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 return values, then the null-amount caveat — every sentence carries information. It is dense with domain jargon (D398, ANAF, OSS) in a single long sentence, which costs a little readability but no waste.

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 burden of describing returns and does so well: grouping dimensions, EUR conversion, payment due date, reference number, ANAF OSS account, and the null-amount condition. Missing only the concrete response shape/field names and any error or eligibility conditions.

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 year, quarter and companyId are already documented in the schema. The description adds only indirect meaning (quarter is the OSS filing quarter) and no format, default, or override semantics beyond the schema; baseline 3 applies.

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: a quarterly OSS (EU One Stop Shop) VAT view grouped by member state, rate and currency. It is clearly distinct from a generic VAT report, but it never names the sibling reports_vat to draw the contrast explicitly.

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: an agent can infer it is the right tool when it needs the EU OSS quarterly breakdown, but there is no explicit when-to-use statement, no exclusion (e.g., 'for domestic VAT use reports_vat'), and no prerequisites such as the need for an OSS-registered VAT code.

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