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

Annotations already declare readOnlyHint=true, so no destructive actions. The description adds valuable context: it is an estimate dependent on exact deductions and payments, and is informative only. This goes beyond the annotations to clarify limitations and legal basis.

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 two sentences, front-loaded with the primary function, followed by a clarifying limitation. Every word adds value, no redundancy. It is appropriately sized for the tool's simplicity.

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 no output schema, the description could mention what is returned (estimated amount). However, the tool is a simple estimator and the description implies a numeric result. With full schema coverage and annotations, it is largely complete, lacking only explicit output description.

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%, baseline 3. The description adds meaning by noting that deductions do not apply for RESICO PF, and it mentions 'ingresos y deducciones' aligning with schema. This extra detail about parameter applicability enhances semantics.

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 clearly states the tool estimates annual ISR based on regime, income, and deductions, using specific legal references (Art. 152, Anexo 8 RMF 2026). The verb 'ESTIMA' and resource 'ISR anual' are specific, and the description implicitly distinguishes from siblings like fiscal_isr_retencion which deals with withholding.

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 description explains the tool is an estimate and not tax advice, implying it should not be used for final calculations. However, it does not explicitly state when to use this tool versus alternatives (e.g., fiscal_isr_retencion for withholding), nor does it mention prerequisites or exclusions.

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