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

With no annotations provided, the description carries the full burden. It discloses the calculation method (real accumulated 12 months), the output (new rent by both indices and the difference), and the source (Central Bank). It does not mention any side effects, but as a calculation tool it is implicitly read-only. This is transparent enough.

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 sentences, front-loaded with the core purpose and output, followed by parameter requirements. No unnecessary words.

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?

The description covers the core purpose, the calculation basis, and the output format. For a simple two-parameter calculator with no output schema, this is sufficient. It could mention the default index or edge cases, but those are already in the schema. Slight gap: it doesn't explicitly state the index default, but the schema does.

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 already provides descriptions for both parameters (current_rent as monthly rent in R$, contract_index as the index with default igpm). The description just reiterates required/optional status and naming, adding no semantic value beyond the schema. With 100% schema coverage, baseline is 3.

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 states it calculates annual rent adjustment using the 12-month accumulated IGP-M or IPCA (Central Bank), shows the new value for both indices and the difference. This is specific and distinguishes from sibling tools like calculate_multas_aluguel (rent fine) and calculate_rent_affordability.

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 does not provide any guidance on when to use this tool versus alternative rent-related calculators. It only states required/optional parameters, which is about invocation, not usage context. No explicit when/when-not or alternatives are mentioned.

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