compare_assets

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

Annotations already provide readOnlyHint, idempotentHint, and openWorldHint. Beyond that, the description discloses output behavior: returns are nominal and in each asset's own currency, mixed currencies are flagged, and ratios are fractions (0.12 means 12%). It also specifies a shared date window, adding valuable context not present in the schema.

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 three focused sentences: the first states the action and metrics, the second gives usage guidance, and the third clarifies output formatting. Every sentence earns its place, and the core purpose is front-loaded. No redundant or filler text.

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 there is no output schema, the description explains the return values (returns, volatility, max drawdown per asset) and formatting details (fractions, currency flagging). It covers the key aspects needed to call and interpret the tool, though the exact response structure is not fully specified, which would require inference by the 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 100% description coverage, so the baseline is 3. The description mostly mirrors the schema's constraints (2-10 symbols, date window) and does not add per-parameter meaning beyond the schema's own descriptions. It provides no additional details for start, end, or period beyond the 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 states a specific verb and resource: 'Put 2 to 10 assets side by side' and enumerates the metrics returned (total and annualized return, volatility, maximum drawdown). It explicitly notes returns are nominal, which differentiates it from the sibling compare_real_return, and clarifies it compares multiple assets or an asset against an index, setting it apart from single-asset tools.

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 gives a clear usage context: 'Use it to compare assets or an asset against an index.' It also conveys important usage nuances about mixed currencies and fraction formatting. However, it does not explicitly name alternatives or state when not to use the tool, such as for real (inflation-adjusted) returns.

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