xoomar-mcp

Schedule 13D and 13G holders

large_holders

Find holders owning over 5% of a US stock from SEC Schedule 13D/13G filings, with shares, class percentage, and filing dates. Query by ticker or latest filings.

Instructions

Holders above 5% from Schedule 13D (active) and 13G (passive) cover pages: holder, shares, percent of class, filing date. For a symbol or the latest filings.

Tool call template

This tool declares no required parameters. Add optional parameters from the input schema as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {},
    "name": "large_holders"
  }
}

Input Schema

Name	Required	Description
`days`	No
`form`	No
`sort`	No
`symbol`	No	US ticker symbol, e.g. GME. Class shares as on the SEC list, e.g. BRK-B.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.1Sep 13, 2026

TDQS

C2.9/5.0

Behavior2/5

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

No annotations are provided, so the description carries the full behavioral burden. It does not state whether the tool requires a symbol, what happens if none is given, pagination/rate limits, or any permission requirements. The only behavioral hint is 'active' vs 'passive' for 13D vs 13G, which is minimal.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single efficient sentence fragment that front-loads the key concept (5%+ holders, 13D/13G) and then lists output fields. It is compact and wastes little space, though it is somewhat dense and could be clearer.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given 4 parameters (0 required), 25% schema description coverage, and no output schema or annotations, the description should do much more to explain parameter semantics and behavior. It only covers the returned fields and hints at usage, leaving critical gaps for correct invocation.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 25% (only the symbol parameter is described). The description does not explain the 'days', 'form', or 'sort' parameters at all, so an agent has no guidance on how they affect results. This is a significant gap that the description fails to compensate for.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb+resource: it returns 5%+ holders from Schedule 13D/13G cover pages, and lists the returned fields (holder, shares, percent of class, filing date). This clearly distinguishes it from sibling fund_holders (fund ownership) and insider_trades. It is clear but does not explicitly name or differentiate against those siblings, so a 4.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The phrase 'For a symbol or the latest filings' implies the two usage modes (filter by symbol vs. get latest filings), which is useful context. However, there is no explicit when-to-use, when-not-to-use, or named alternative, so it is only implied guidance.

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