Retrieve S&P 500 constituent companies and key details to track index performance and analyze member stocks.
Access detailed data on the S&P 500 index using the S&P 500 Index API. Track the performance and key information of the companies that make up this major stock market index.
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v2.9.0Input schema / $schemaPrevious value: -"http://json-schema.org/draft-07/schema#"New value: +"https://json-schema.org/draft/2020-12/schema"v1.0.0Input schema / additionalPropertiesRemoved value: -falseDoes the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description does not contradict the safety hints provided in annotations. It adds helpful context regarding the data source (S&P 500 Index API) and the type of information covered (performance and key info).
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 concise and easy to understand. However, the first sentence is slightly verbose ('using the S&P 500 Index API') and could be tighter to focus purely on the functional output.
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 that this is a parameter-less tool, the description is sufficiently complete. It provides a clear boundary on the index it covers and the nature of the data available, without needing to explain hypothetical parameters.
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?
Since the tool has zero input parameters, the description's semantic value lies in defining the scope of the returned data (performance and key information of S&P 500 constituents), acting as a necessary high-level summary.
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 states the purpose: to access detailed data and track performance of companies within the S&P 500 index. It specifically identifies the resource and distinguishes itself from tools focusing on other indexes like Nasdaq or Dow Jones.
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?
Usage is implied when S&P 500 constituent data is needed. However, it does not provide guidance on when to use this tool versus other market data or search functions available in the large list of sibling tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.