get_market_indices

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. 'Fetch the latest data' implies a read operation but doesn't disclose what data fields will be returned, whether the data is real-time or delayed, or any rate limits. The description is too thin to convey behavioral traits beyond the basic fetch action.

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?

A single, front-loaded sentence delivers the essential purpose without any filler. Every word is meaningful, and the description is well-sized for a tool with no parameters.

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's low complexity (zero parameters, no output schema), the description adequately names the resource and action. However, it could be improved by listing example indices (e.g., S&P 500, Dow, Nasdaq) or clarifying that it returns current values only. Still, for a simple list tool, the description is reasonably complete.

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 tool has zero parameters, so the schema provides no properties to explain. The description adds a slight semantic hint by specifying 'major US market indices,' which implicitly defines the scope of the return set. With no parameters, the description doesn't need to compensate, so the baseline of 4 is appropriate.

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 'Fetch the latest data for major US market indices' clearly identifies the action (fetch) and the resource (major US market indices), distinguishing it from sibling tools that target individual stocks, company info, historical data, or news. The scope is specific enough for an agent to select it for index-related queries.

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?

There is no explicit guidance on when to use this tool versus the sibling tools (e.g., 'Use for market indices; for individual stocks use get_stock_price'). The description only states what it does, so the agent must infer usage context from the tool name and sibling list, which is insufficient.

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