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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds real context beyond that — it is framed as client-facing evidence and explicitly includes days with no one present and off-site records, telling the agent the report fills gaps rather than only listing existing entries. It does not discuss permissions or the multi-company filter behavior.

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 with the scope and outputs, then the example queries, which is a sound structure. The trailing English gloss "Site coverage report for a client." is largely redundant with the preceding sentence.

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?

With no output schema, the description carries the burden of describing returns and does so by enumerating the four result categories. Combined with fully documented parameters, an agent has enough to call it correctly; only edge behavior (e.g., how off-site records are counted) is left implicit.

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 sitio, desde, hasta and empresa are already documented with formats and defaults. The description only restates the site-plus-date-range shape and adds nothing about the optional empresa filter, so the baseline of 3 applies.

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 resource and scope ("Para un sitio y un rango de fechas") and then enumerates exactly what it returns: days with staff, headcount per day, days with nobody, and off-site registrations. That output profile distinguishes it from siblings like registro_de_jornada or asistencia_del_dia without needing to name them.

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?

Gives concrete trigger questions ("¿cubrimos la caseta norte en octubre?", "¿cuántas personas hubo cada día en el hospital?") and a use case (preparing a client's monthly report), which is clear when-to-use guidance. It stops short of stating when to prefer a sibling tool instead, so it does not reach the top of the scale.

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