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

Annotations only declare readOnlyHint and openWorldHint, so the description carries most of the behavioral load and does so well: it discloses substring/case/accent-insensitive matching except for '(valor exato)' fields, that responses include total_disponivel, and the pular+limite pagination pattern. This is context an agent needs and that neither annotations nor schema provide.

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 overview and defaults are front-loaded, then a clean per-visao breakdown. It is longer than strictly necessary, with some repetition of filter lists that also appear in the schema, but every section is scannable and earns its place.

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 10-parameter tool with five distinct visões, the description covers each mode, its filters, the default, pagination, and filter-matching semantics. An output schema exists, so return-value explanation is not required, and nothing needed to call it correctly is missing.

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 coverage is already 100%, so the schema documents formats and per-visao applicability. The description still adds value by consolidating which filters apply to which visao and clarifying date formats and the 'fazenda' default behavior. Since the schema already repeats much of this, a 4 rather than 5.

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 opening sentence gives a specific verb-and-resource statement: rain registered by pluviometer, per collection, per plot, or consolidated in the harvest, plus the pluviometer registry. It also implicitly distinguishes itself from the write sibling lancar_chuva by framing the tool as a query. An agent can tell exactly what this returns without opening the 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?

The description enumerates all five 'visao' values with their applicable filters and explicitly routes the agent: use 'pluviometros' to count, use 'pluviometros_talhoes' for the coverage mapping, and the default when 'visao' is omitted. It also adds a strong operational rule ('call once with the limit you will use; never repeat changing only the limit') and points to lancar_chuva for the ID to use.

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