get_historical_trend

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It only states the return type (historical series and percentage change) but does not mention whether the operation is read-only, any side effects, authentication requirements, rate limits, or data freshness. The description adds minimal behavioral context beyond the obvious.

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 extremely concise: one sentence stating the purpose, followed by a bullet-like listing of arguments. Every word earns its place; there is no filler. The main action is front-loaded, and the argument descriptions are compact.

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 tool with 2 parameters, no annotations, and an output schema (unseen), the description covers the basic return but lacks details. It does not explain what 'historical series' entails (e.g., frequency, date range, format) or any constraints on 'days'. The description is adequate but leaves room for ambiguity about the exact output structure.

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 description coverage is 0%, so the description must compensate. It explains 'commodity' as the name of the commodity and 'days' as the window of days with a default of 30. This adds value beyond the schema's type and default, but it does not specify valid commodity identifiers, allowed range for days, or format constraints. The description partially clarifies parameter meaning.

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 returns historical price series and percentage change for a commodity. It uses a specific verb ('retorna') and resource ('série histórica de preços'), distinguishing it from sibling tools like get_commodity_price (current price) and list_commodities.

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 alternatives. It lacks explicit context like when to prefer historical data over current prices or how this tool differs from calculate_margin or generate_report. No exclusions or prerequisites are mentioned.

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