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Johnhyeon

StockLens

by Johnhyeon

get_us_holders

Read-onlyIdempotent

Retrieve US institutional and mutual fund holders' 13F filings for any US ticker to see who owns the stock, including major holders like Vanguard.

Instructions

US institutional holders — 기관·뮤추얼펀드 보유 현황 (13F holdings). "AAPL institutional holders", "Vanguard 보유", "13F holdings", "who owns" 같은 질문에 사용합니다.

Args: ticker: US 티커

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
tickerYes

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
resultYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.4.0

TDQS

A4.2/5.0
Behavior4/5

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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds meaningful context by specifying the data source and nature of the holdings (13F institutional and mutual fund holdings), which goes beyond the structured annotations.

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

Conciseness5/5

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

The description is compact, front-loaded with core meaning, and uses every line for a purpose: definition, example queries, and parameter hint. No filler or redundant explanation is present.

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

Completeness4/5

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

For a single-parameter, read-only tool with an output schema, the description covers what the tool returns and how to invoke it. Additional details like filing-period coverage would be nice but are not necessary for correct use.

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

Parameters3/5

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

The schema has no description for 'ticker', and the description adds only 'US 티커' (US ticker). This is minimal but adequate for a single required string parameter; adding an explicit example like 'AAPL' would strengthen it.

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

Purpose5/5

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

The description states the resource precisely: US institutional holders and 13F holdings, backed by example queries like 'AAPL institutional holders' and 'Vanguard 보유'. It is clearly distinct from close siblings like get_us_insider or get_us_short, even without naming them explicitly.

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

Usage Guidelines4/5

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

It explicitly maps the tool to natural-language questions such as 'AAPL institutional holders', '13F holdings', and 'who owns'. This gives clear when-to-use context, though it does not mention alternative tools or circumstances where it should not be used.

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