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

With no annotations provided, the description carries full responsibility for behavioral disclosure. It openly states that unresolvable or history-insufficient symbols are skipped and reported in 'warnings', and that rank 1 = best. It also surfaces pricing. However, it does not clarify how 'best' is interpreted for each metric (e.g., lower volatility vs. higher return), which is a notable gap.

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 two tight sentences plus a pricing parenthetical, with no fluff. The first sentence states the core action and metric list, the second covers error handling and output structure, and the pricing note is informative. Every clause earns its place.

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 no output schema and no annotations, the description adequately covers the return shape (list of {ticker, value, rank, currency}), the skip/warning behavior, and the ranking definition. It falls short only on defining per-metric 'best' and leaving the range parameter semantically open, but overall the tool is sufficiently described for a competent agent.

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 0% coverage, so the description must add meaning for parameters. It does clarify the 'metric' parameter by listing its allowed values and the 'tickers' parameter by requiring at least two and explaining skip behavior. However, the 'range' parameter is entirely unexplained, and the description does not elaborate on how range interacts with the metric or the rankings.

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 states a specific verb ('Rank') and resource ('two or more tickers') with a clear scope: ranking by a single metric. It lists the allowed metrics and explicitly describes the output format, distinguishing it from sibling tools like compute_stats or screen, which have broader or different purposes.

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 implies usage when comparing multiple tickers by a metric, but it does not explicitly mention when not to use the tool or provide alternative tool names. Sibling tools like screen or compute_stats have overlapping capabilities, and no exclusions or fallback guidance are given.

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