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

With no annotations, the description carries the burden of disclosing behavior. It states the tool accesses historical data and analyzes changes, which conveys a read-only, analytical function. However, it does not disclose return format, date ranges, or any limitations, leaving some uncertainty about output shape or scope.

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 sentences and relatively concise. The first sentence 'using the Historical Nasdaq API' is somewhat redundant and adds little value, but the second sentence provides concrete information about composition changes. Overall efficient, but not perfectly lean.

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?

For a tool with no parameters and no output schema, the description is reasonably complete. It states the core functionality and the aspect of the data (composition changes). Minor gap: it does not explicitly mention what the output will look like, but given the simplicity, this is acceptable.

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 input schema has zero parameters, so the baseline for parameter semantics is 4. The description does not need to explain parameter syntax, and it adds no param-related details. The baseline is appropriate since no parameters exist to describe.

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 specifies the verb 'Access' and 'Analyze' with the resource 'historical data for the Nasdaq index', and explicitly states the tool's focus on composition changes, additions, and removals. This differentiates it from sibling tools like getHistoricalSP500Changes or getHistoricalDowJonesChanges by naming the index.

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 the use case: when you need Nasdaq index historical composition changes, this is the tool. However, it does not explicitly mention alternatives or exclusions, such as 'for S&P 500 use getHistoricalSP500Changes'. This is clear context but lacks explicit when-not-to-use guidance.

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