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

With no annotations, the description carries the full burden and does substantial work: it discloses the data source (SEC Form N-PORT filings) and enumerates the returned fields including allocation weight, market value, shares held and reporting date. It stops short of noting the quarterly filing cadence / reporting lag or coverage limits, which matter for interpreting staleness.

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?

Three sentences, front-loaded with the core action and data source, then return fields, then usage. The closing clause about 'diversified single-stock exposure without single-stock risk' is mildly promotional but does encode a legitimate user scenario, so little is wasted.

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?

Four parameters all documented in-schema, no output schema and no annotations, and the description covers purpose, data provenance, output fields and usage context. The main residual gap is data freshness/cadence and any indication that results are limited to filers reporting that ticker, but overall it is sufficient to call the tool correctly.

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?

Schema description coverage is 100%, so the schema already explains ticker, limit, sort_by and fund_type fully. The description adds only light reinforcement by framing weight as 'allocation weight (concentration)' and market value as dollar exposure, which is the semantic intent behind the sort_by enum but not new parameter-level detail.

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?

States a specific verb and resource ('institutional reverse-lookup across SEC Form N-PORT filings to find ETFs, Closed-End Funds, and Mutual Funds that hold a specific stock') and specifies the direction of the lookup, which implicitly separates it from the sibling get_fund_holdings that goes fund -> holdings. The fund universe covered (ETF/CEF/MF) is also named.

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?

Provides a clear when-to-use clause ('when users want to know what funds hold a stock or want diversified single-stock exposure'), which maps a real user intent onto the tool. It never explicitly names get_fund_holdings as the inverse alternative or states when not to use it, so routing still requires the agent to infer the directionality.

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