es__check_b2b_mandate_applicability

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

With no annotations provided, the description carries the full disclosure burden. It does disclose a meaningful behavioral trait — 'Aplica la lógica de exclusión mutua del Real Decreto 254/2025' — which tells the agent the tool returns a single mutually-exclusive regime. It does not state whether the computation is local, synchronous, or side-effect free, which for a determination tool is a moderate but not critical 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?

Three short sentences, each earning its place: the first surfaces the purpose, the second enumerates the regimes and inputs, the third states the governing legal logic. The purpose is front-loaded and there is no filler or redundant restatement of the tool name.

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?

Together, the description, input schema, and output schema cover the decision scope, decision inputs, mutual-exclusion rule, and return structure. The main omissions are the absence of any guidance on how this tool relates to the overlapping sibling es__detect_regional_regime, and the entity_type input not being woven into the narrative — though the schema adequately documents it.

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 all four parameters already carry types, defaults, and constraints, meeting the baseline. The description adds modest conceptual value by tying turnover, province code, and SII enrollment to the regime-decision logic, but it provides no additional format or constraint details beyond what the schema already contains.

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 verb and resource — 'Determina el régimen de facturación electrónica aplicable' — and enumerates the exact regimes covered (VERI*FACTU, SII, TicketBAI, NaTicket) along with the decision inputs. This is clear, but it does not explicitly differentiate from the closely named sibling es__detect_regional_regime, which appears to overlap on regional-regime detection.

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?

The usage context is implied by listing the decision drivers ('a partir del volumen de operaciones, código de provincia y enrolamiento en SII'), which suggests an agent should call this when those data are available and a regime determination is needed. However, there is no explicit when-to-use/when-not-to-use guidance and no mention of alternatives such as es__detect_regional_regime, leaving selection among the siblings to inference.

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