get_igpm

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It explains that the value is a monthly percentage variation, but it does not disclose how the 'ultimos' parameter affects results, what the response contains, or any data-source/time-period behavior beyond 'mensal'.

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 a single compact sentence that front-loads the core meaning ('IGP-M — variação mensal (%)') and adds a practical use case. Every word earns its place with no filler.

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 simple one-parameter data retrieval tool, the description gives enough to understand the metric and its typical use, but it is incomplete around the 'ultimos' parameter semantics and the expected response. The absence of annotations and output schema makes this gap more noticeable.

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 one parameter ('ultimos') with 0% description coverage, and the tool description does not explain it. The Portuguese word 'ultimos' hints at 'last N periods', and the word 'mensal' suggests monthly data, but the description adds no explicit meaning beyond the schema.

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 clearly identifies the resource (IGP-M) and metric (mensal variation percent), which distinguishes it from sibling tools like get_selic and get_cdi. It lacks an explicit verb like 'returns' or 'gets', but the meaning is unambiguous.

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 states a concrete use case: 'Usado em reajuste de aluguéis/contratos' (used in rent/contract adjustments), which gives the agent context on when to call it. However, it does not mention when not to use it or compare it to sibling tools, relying on the tool name alone for differentiation.

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