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

Beyond the sparse annotations, it discloses partial-update semantics, enum normalization, and the non-obvious `outros_contatos` full-replacement requirement with the complete set of fields the API demands. It also tells the agent that errors identify the missing field. This is strong behavioral context; it only stops short of describing return values or auth requirements.

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?

The description is dense but purposeful: every sentence conveys operational constraints, gotchas, or field requirements, and the create/update distinction is front-loaded. It is longer than average, but that length is justified by the tool's complexity; a little redundancy remains around partial-update phrasing.

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 mutating, no-output-schema tool with several enums and a major edge case, the description covers the essential calling contract: required fields, partial update rules, replacement behavior, error hints, and bulk support. It is incomplete mainly in not explaining `account` and in leaving the relationship to `contaazul_person_write_update` implicit.

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?

With 0% schema coverage, the description carries the full burden and does so well for `data`, `id`, and `ids`: it documents JSON format, required create fields, partial update semantics, enum values, and bulk use. The only parameter left unexplained is `account`, and the `action` selector referenced in the text is not present in the schema, which is a residual gap.

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 opens with a clear verb+resource ('Cria ou atualiza uma pessoa') and spells out create/update modes with required fields, so an agent can tell what the operation acts on. However, it never names or contrasts the sibling `contaazul_person_write_update`, and the update instructions plus '[Flattened action: create]' blur whether this tool is create-only.

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?

It gives operational conditions for action=create vs action=update and says what each requires, which is useful context for choosing payload shape. But it gives no explicit when-to-use/when-not-to-use guidance relative to the sibling update tool and no exclusions, leaving the agent to infer that this tool may also update.

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