get_roll_yield

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

Annotations already declare read-only and non-destructive behavior. The description adds valuable context about the df parameter: it fetches data from dailyBar internally if df is None, and passing df speeds up computation. This discloses internal data fetching and performance implications, which goes beyond the annotations.

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 and well-structured: a short purpose statement followed by a clean parameter list. Each line is necessary and front-loaded with the core functionality. No wasted 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?

While the description explains inputs and purpose well, it does not mention what the function returns (e.g., a scalar, tuple, or DataFrame). With no output schema, this is a notable gap. However, given the tool's relative simplicity and strong annotations, it remains adequately complete for basic usage.

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 fully compensates by explaining every parameter: date format (YYYYMMDD), var examples (RB, AL), symbol examples (rb1810, rb1812), and df's role and optionality. This is detailed and actionable, far exceeding baseline.

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 computes roll yield for a specified trading day, either for a specified variety using main/second main contracts or for any two given contracts. This is specific and distinguishes it from siblings like get_roll_yield_bar which likely returns a time series. The purpose 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 provides no guidance on when to use this tool versus alternatives. It does not mention exclusions, prerequisites, or use cases. The only contextual hint is the performance note about passing df, which does not address tool selection.

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