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

Annotations already declare readOnlyHint=true, idempotentHint=true and openWorldHint=false, so the safety profile is covered. The description adds real value beyond that by naming the data source (official TSE acervo) and the two possible return shapes (the matching file, or the registered hash). It does not disclose what happens on a mismatch, what a match result looks like, or the semantics of the batch parameter.

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?

A single well-formed sentence that front-loads the primary operation and then the inverse case, with no filler. The inline filename examples earn their space by disambiguating the 'arquivo' input.

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 and zero schema descriptions on 4 parameters, the description should explain both the batch 'itens' path and the 'ano' scoping, plus mismatch behavior. It describes only the single-hash/single-file case, so an agent could easily miss that the tool accepts arrays and year filters — a material gap for a tool whose only structured documentation is bare property names.

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 0% across 4 parameters, so the description carries the full burden — and it only covers two of them. The filename format examples (o03221pr7691000660045-bu.dat, br-c0001-e006258-u.json) are genuinely useful added semantics for 'arquivo', but 'ano' and 'itens' are never mentioned, leaving the agent unaware that batch verification and year scoping exist at all.

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 names a specific operation (check whether a SHA-256 matches a hash registered for an official TSE file in the acervo, and identify which file) and covers the inverse lookup (filename → registered SHA-256). No sibling tool (eleicoes_totais, eleicoes_conferir_bu_impresso, etc.) performs hash verification, so the tool is unambiguously distinguishable. The concrete filename examples make the resource being operated on unmistakable.

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 two clauses effectively describe two usage modes (verify a given hash, or look up a hash by filename), so intended usage is inferable. However there is no guidance on when to prefer this over the related document-checking siblings, no prerequisites, and no exclusions or mention of which mode applies when both inputs are supplied.

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