fiis_ranking

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 that the tool is read-only/descriptive ('Descritivo, não é recomendação'), uses only clean values (no flags), and requires liquid funds. It also mentions the API key requirement and that the ranking scans the entire universe. This is good behavioral context, though it doesn't detail rate limits or response format.

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 well-structured: a clear first sentence summarizing the tool, followed by data source and filtering details, then a note on the API key. It's a bit long but every sentence adds value. The parameter section is integrated naturally.

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 ranking tool with one parameter and no output schema, the description covers the key aspects: what it ranks, how it filters, data sources, and the API key requirement. It doesn't explain the output format (e.g., columns, ordering), but the description of the ranking criteria (P/VP, DY, vacancy) gives a good sense of what to expect.

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 `chave_api` with 0% description coverage, so the description must compensate. It does: it states the parameter is mandatory ('obrigatória'), mentions free/Pro tiers, and gives an example of how the key is used in a sibling tool. This adds meaning beyond the bare 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 states the tool's purpose: ranking FIIs by discount (P/VP), dividend yield (DY 12m), and medians by segment. It specifies the data sources (CVM monthly report + COTAHIST) and the filtering criteria (clean values, liquid funds), which distinguishes it from sibling tools like `fii` (single fund) and `fiis` (likely a list).

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 explains when to use this tool: to get a ranking of the whole FII universe, as opposed to the `fii` tool which is for a specific fund like MXRF11. It also notes the tool is descriptive, not a recommendation, which helps set expectations. However, it doesn't explicitly mention alternatives like `fiis` or `etfs_ranking` for comparison, so it's not a full when/when-not guide.

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