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

Annotations already declare write behavior (readOnlyHint false), idempotency, and non-destructiveness, and the description's "Grava" is consistent with that. It adds the meaningful "nunca invente" constraint, but does not disclose overwrite behavior, auth needs, or what happens to existing values on a partial save.

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 dense but efficient sentences front-load the write action and resources, then the value constraints and guardrail. Nothing is wasted, though the range and enum decoding make it somewhat information-packed.

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 two-parameter write tool with no output schema, the description covers both parameter semantics, their constraints, and the key guardrail about only using user-provided values. Only the save/overwrite outcome is left implicit, which is a minor gap given there is no output schema to explain returns.

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 description adds real meaning beyond the schema: it supplies the valid range 0 < x ≤ 33 for the aliquot and decodes the otherwise-bare enum (1 = competência, 2 = caixa, 3 = outro). This compensates well for the 50% schema description coverage, only lacking the unit interpretation already hinted by the schema example.

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 uses a concrete verb ("Grava") and names the two specific resources (alíquota do Simples Nacional and regime de apuração), which usefully corrects the potentially misleading name/title that sound like it returns answers. It is clear what gets persisted, though it doesn't explicitly contrast with the sibling perguntas_fiscais tool that presumably serves the questions.

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?

Usage is only implied: the agent should call this when a person has supplied fiscal values, reinforced by the guardrail "Só com valores que a pessoa informou; nunca invente." There is no explicit when-not or comparison to perguntas_fiscais, so the when-to-use guidance is inferred rather than stated.

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