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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety and scope are covered structurally; the description reinforces this by framing the tool as explanatory content (capabilities, exclusions, pricing, onboarding) rather than data mutation. It does add useful context about the answer's content but says nothing about the response shape or how current the pricing information is.

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?

One front-loaded sentence carries the coverage list and the usage trigger, with no filler. The trailing English restatement ('What Chato is and how to get started') is a partial duplicate of the Spanish clause and adds little, costing it the top band.

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?

For a zero-parameter, no-output-schema informational tool, the description is nearly sufficient: it delimits the topic scope and tells the agent when the topic applies. A brief note that the result is narrative guidance (not tenant-specific account data) would close the remaining gap.

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?

The tool takes zero parameters, which is the baseline-4 case; there is no argument surface that needs explaining. The description correctly implies a parameterless, prompt-driven informational call rather than suggesting any inputs are required.

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?

Names a specific informational resource ('Qué es Chato') and enumerates exactly what it covers: what the product does (WhatsApp attendance control for staff at worksites, client sites and multiple locations in Mexico), what it does not do, pricing and onboarding. This makes it unmistakable against the sibling tools, which are all operational data operations (sitios, asistencia_del_dia, dar_de_alta_empleado, etc.).

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 an explicit trigger list ('pregunten qué es Chato, cómo funciona, cuánto cuesta, si sirve para su caso o cómo conectar su cuenta'), which is strong when-to-use guidance. It stops short of naming when-not-to-use or pointing to a sibling for account-specific data, so it falls just short of the top band.

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