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

Beyond the readOnlyHint annotation, the description reveals key behavioral traits: the deadline calculation rule (17th of next month, adjusted to next business day) and the extension logic based on RFC digit. It also warns 'Informativo, no asesoria fiscal', adding important context.

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 three sentences, concise, and front-loaded with the purpose. Every sentence adds value without repetition.

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 explains what the tool calculates and the logic. However, it does not specify the exact output format or behavior when parameters are omitted, leaving minor gaps.

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%, but the description adds meaning by explaining how `mes` and `rfc6` affect the output (deadline calculation and extension estimation), going beyond parameter names.

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 it provides 'Obligaciones fiscales y fechas limite' for Mexican tax regimes. It distinguishes itself from sibling tools like fiscal_aguinaldo or fiscal_cfdi_validar by focusing on deadlines and extensions.

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 when to use the tool: to calculate payment deadlines with `mes` and estimate extensions with `rfc6`. It does not explicitly exclude alternatives but the context is clear.

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