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

No annotations are provided, so the description carries the full burden. It uses vague terms like 'comprehensive data' and 'real-time movements' but doesn't disclose whether this is a read-only operation, what the output format looks like, or any rate-limit/authentication requirements.

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 short, but the second sentence is vague and includes filler like 'prominent stock exchange' instead of clarifying exactly what data is returned. It could be more precise and front-load the key purpose.

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?

With no output schema and no annotations, the description should explain what 'comprehensive data' means and explicitly mention the constituent list. It doesn't, leaving the return values under-specified for an 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 tool has zero parameters, so the description does not need to document parameter semantics. The baseline of 4 applies because no parameter documentation is required.

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 names the Nasdaq index and mentions 'companies listed on this prominent stock exchange', which implies constituents, but it never explicitly says the tool returns the constituent list. It also doesn't distinguish from sibling tools like getIndexQuote or getHistoricalNasdaqChanges.

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?

No guidance is provided about when to use this tool versus alternatives such as getDowJonesConstituents, getSP500Constituents, or getIndexQuote. There are no exclusions or alternative recommendations.

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