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

Annotations already mark the tool as read-only. The description goes further by emphasizing it never recommends a regime and is purely informative, which reinforces the read-only nature and adds context about the tool's limitations. No contradictions.

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 concise, with two clear sentences front-loaded with the main purpose. It avoids repetition or extraneous details, making it efficient for an AI agent to parse.

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 the tool has 3 parameters and no output schema, the description adequately explains what it returns (factors) and its non-decision-making nature. It provides sufficient context for the agent to understand the tool's role, though a brief mention of the response structure could enhance completeness.

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 baseline is 3. The description does not add new meaning beyond the schema; it merely restates the parameters (tipo_persona, ingresos_anuales, actividad). It aligns with schema content without enhancing parameter understanding.

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 returns factors for choosing a fiscal regime in Mexico, listing specific types of factors (income limits, taxable base, rates, exclusions). It distinguishes itself from sibling tools like fiscal_isr_estimado or fiscal_calendario by focusing on regime selection rather than specific calculations.

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 implies the tool is for informational purposes and not for decision-making, but it does not explicitly guide when to use this tool over alternatives. Given sibling tools like fiscal_isr_retencion and fiscal_recargos, explicit usage guidance could improve differentiation.

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