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

Annotations already declare readOnly/idempotent/non-destructive, so safety is covered; the description goes beyond them by explaining the failure lifecycle (first failure does not alert, worker re-checks in ~30s, only the 2nd consecutive failure becomes major_outage), which is genuine domain behavior an agent should know. It does not cover auth requirements or rate limits, keeping it short of a 5.

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?

Purpose and usage come first, then return-value detail — properly front-loaded. The return section is dense but each clause (state semantics, lastCheck fields, lastFailure enums, ocorrenciaAberta) carries information not available elsewhere; only the parenthetical PT-BR aside is slightly expendable.

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?

There is no output schema, so the description takes on return documentation and does it thoroughly: monitor/state, lastCheck (ok, latency, error, timestamp), lastFailure (reason enum values, httpStatus, message), and ocorrenciaAberta with null semantics. An agent has everything needed to interpret the response.

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?

Only one parameter and the schema already documents it at 100% coverage, including the pointer to listar_monitores. The description adds no syntax or format detail for `id`, so this sits at the baseline 3 where the schema does the work.

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 verb+resource — detail of a monitor — and enumerates what is returned (configuração, estado, último check, motivo da falha). It distinguishes itself from siblings by naming testar_url and listar_checks as the tools for other jobs, so an agent can route correctly without opening any schema.

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 ('quando listar_monitores mostrar um monitor fora do ar ou failing e o usuário quiser saber por quê') and names two alternatives with their conditions: testar_url for running a check now, listar_checks for history. Nothing is left to inference.

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