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

Adds real context beyond annotations: partial-update semantics ('pass only the field you want to change'), the fact that no fiscal validation is performed, the display-only nature of hide_retention, and the return payload. However, annotations declare destructiveHint=true and the description never addresses destructiveness — it does not say the previous defaults are overwritten or whether already-created invoices are unaffected, which is exactly what an agent needs before calling a destructive tool.

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 purpose sentence followed by two short behavioral clauses and a return statement; every sentence adds information. The bilingual parentheticals cost some length but are justified for user-terminology matching.

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?

No output schema exists, and the description compensates by stating what is returned (payment term, IVA rate, retención visibility). Scope and partial-update behavior are covered; the only material gap is the unaddressed destructive/overwrite consequence of changing tenant-wide defaults.

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 100%, so the baseline is 3, but the description adds the non-obvious partial-update contract and Spanish field aliases (plazo de pago por defecto / tipo de IVA por defecto) that help map user terminology to the English parameter names. The hide_retention caveat is also restated in the description's return sentence.

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 and resource with scope: 'Set the tenant defaults for new invoices', then names the exact fields (payment term in days, IVA rate). It does not name the obvious counterpart get_invoice_defaults, so an agent must infer the read/write split from the verb alone.

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 'tenant defaults for new invoices' framing and the 'pass only the field you want to change' instruction, but there is no explicit when-to-use, when-not, or reference to get_invoice_defaults for reading current values. Nothing warns the agent that this overwrites tenant-wide settings rather than per-invoice values.

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