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

Annotations already cover read-only, idempotent, non-destructive and open-world, so the description rightly spends its words elsewhere: data source (SEC N-PORT), staleness ('latest'), the degraded-path behavior (bond/cash/fund-of-funds funds return coverage.covered = false and no boat), and licensing. It stops short of describing response shape or size/rate limits, which matters somewhat given there is no output schema.

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?

Front-loaded with the verb and scope, and every clause carries information (source, coverage universe, health categories, edge case, license). It loses a point for dense, jargon-heavy phrasing — 'no boat' and 'coverage.covered' appear without explanation, forcing the agent to guess at a field name.

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?

With no output schema and one simple input, the description does most of the work an agent needs: it names the data source, the matched-filer concept, the Health Watch event categories, the share-of-fund measure, and the non-common-stock fallback. Only the actual response envelope beyond coverage.covered and the undefined 'boat' term are left unexplained.

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 coverage is 100% and the single parameter already documents the ticker with an example. The description adds only that the fund must be a US-registered ETF and lists sample tickers; useful framing, but nothing about ticker format, case sensitivity, or failure behavior for unknown tickers, so it stays at the baseline for a fully documented param.

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 ('look through') plus a precisely scoped resource: the latest SEC N-PORT holdings of a named US ETF, each stock matched to its SEC filer, plus Health Watch flags. The content is specific enough to separate it from get_etf_league (fund-level ranking) and get_portfolio_health (portfolio-level), and concrete ticker examples anchor the scope.

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?

Usage is implied by the ticker examples and the 'For stock funds: ...' edge case, but the description never says when to choose this over get_etf_league or get_portfolio_health, nor states any prerequisite. The 'Display only, not a rating' caveat sets expectations but is not selection guidance.

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