preco_diario

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

No annotations are provided, so the description carries the full burden. It describes the function as retrieving daily prices, which is a read operation, but does not disclose any behavioral traits like rate limits, data freshness, or required permissions.

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 concise with a main sentence and a bullet-style Args list. Every sentence provides value, no redundancy, and information is front-loaded.

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?

Given the tool simplicity (2 parameters, output schema present), the description fully covers purpose, valid inputs, and parameter constraints. The output schema handles return value documentation, so completeness is achieved.

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 compensates by listing example products ('soja', 'milho') and specifying defaults and constraints for 'dias' (default 5, max 60). This adds meaning beyond the schema's type and required fields.

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 provides daily spot prices for Brazilian agricultural commodities, lists products and parameters. However, it does not explicitly differentiate from sibling tools like balanco or clima, which also deal with agricultural data.

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 includes parameter details and defaults but lacks explicit guidance on when to use this tool versus alternatives like estimativa_safra or futuros_b3. Usage is implied but not stated.

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