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lkcair

yfinance-ai MCP server

by lkcair

get_fund_sector_weights

Read-onlyIdempotent

Retrieve sector allocation percentages for an ETF or mutual fund by ticker symbol to assess industry exposure and diversification.

Instructions

Get sector allocation/weights for an ETF or mutual fund.

Args: ticker: Fund ticker symbol (e.g., 'VOO', 'SPY', 'QQQ')

Returns: Sector allocation percentages for the fund

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
tickerYes

Output Schema

TableJSON Schema
NameRequiredDescriptionDefault
resultYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.1.0

TDQS

B3.4/5.0
Behavior3/5

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so the safety and side-effect profile is fully covered. The description adds that the return is sector allocation percentages, which is useful but modest; it does not disclose anything further about granularity, coverage, or edge cases beyond what the annotations and output schema carry.

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 short and front-loaded, stating purpose in the first sentence before the Args/Returns blocks. The docstring-style sections are slightly redundant given the output schema covers return values, but nothing is bloated or padded.

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-required-parameter, read-only tool with full annotation coverage and an existing output schema, the definition supplies enough to call it correctly: purpose, the one parameter with examples, and a return summary. The notable gap is guidance on when this tool is preferred over its many fund/sector siblings.

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

Parameters4/5

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

Schema description coverage is 0%, so the description must carry the parameter meaning, and it does: it labels ticker as the fund ticker symbol and supplies concrete examples ('VOO', 'SPY', 'QQQ'), clarifying that equity-index fund tickers are expected. This meaningfully compensates for the empty schema description.

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?

States a specific verb (get) and resource (sector allocation/weights) scoped to funds (ETF or mutual fund), so an agent knows it returns a fund's sector breakdown. It does not, however, explicitly distinguish itself from nearby siblings like get_fund_holdings or get_sector_overview/get_sector_performance, so differentiation is left to inference.

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

Usage Guidelines2/5

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

There is no statement of when to use this tool versus alternatives, no exclusions, and no prerequisites. The only implicit signal is 'for an ETF or mutual fund', which tells the agent the input domain but not when this tool is the right choice over get_fund_holdings or the sector_* tools.

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