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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds real domain behavior beyond that: what pode_emitir means, that 'aviso' explains a blockage, and how situacao_fiscal maps to eligibility. It doesn't discuss refresh/caching or whether the list can be empty.

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?

Two sentences, front-loaded with the listing purpose and then the critical pre-emit rule. The parenthetical field enumeration is dense but earns its place since no output schema exists to carry those names.

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 supplies the return field names, the meaning of the status fields, and the precondition for the downstream emit tool — enough for an agent to call it and act on the result. Nothing material is missing for a zero-parameter read tool.

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 schema has zero parameters, so the baseline applies. The description does not need to document inputs but usefully documents the per-row output fields an agent will receive.

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 ('Lista') plus resource ('as empresas (CNPJs) conectadas a este install') and enumerates exactly what each entry contains (company_id, razão social, município, validade do certificado, situacao_fiscal, pode_emitir). The scoping phrase 'conectadas a este install' cleanly separates it from the NF-e operation siblings such as notafiscal_emitir_nfse or notafiscal_listar_nfse.

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?

'CHAME ANTES DE EMITIR' gives an explicit trigger tied to the sibling emit tool, and it explains the eligibility condition (only pode_emitir=true / situacao_fiscal=Active can emit). It never states a when-not case nor names alternatives beyond the implicit emit workflow, but the proactive guidance is unusually clear for a list tool.

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