The ETF Holder Bulk API allows users to quickly retrieve detailed information about the assets and shares held by Exchange-Traded Funds (ETFs). This API provides insights into the weight each asset carries within the ETF, along with key financial information related to these holdings.
| Name | Required | Description | Default |
|---|---|---|---|
| part | Yes | Part number (e.g., 0, 1, 2) |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, but it only describes the content of the response (holdings, weights, financial info). It fails to disclose the pagination behavior implied by the 'part' parameter or any other operational details like rate limits or required authentication.
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 long and conveys the core purpose without excessive wording. The second sentence somewhat repeats the first, but overall it is concise and readable.
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?
The tool appears to be a paginated bulk endpoint based on the 'part' parameter, yet the description does not explain how pagination works or that multiple calls are needed to retrieve all data. This is a major omission given the lack of an output schema.
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 fully describes the sole parameter 'part' as a part number (e.g., 0, 1, 2). Since schema coverage is 100%, the description adds no additional meaning about the parameter or its role in the bulk retrieval process.
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 that the tool retrieves ETF holdings data, including asset weights and key financial information. The phrase 'ETF Holder Bulk API' indicates a bulk operation, but it doesn't explicitly distinguish this from similar sibling tools like getFundHoldings.
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 on when to use this tool versus alternatives. There is no mention of bulk scenarios, exclusions, or prerequisites, leaving the agent without direction on choosing this over other holding-related tools.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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