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

No annotations are provided, so the description takes full responsibility for behavioral disclosure. It clearly explains the behavior when the ticker is not an ETF (is_etf=false, holdings empty) and when it's a real ETF but holdings aren't ingested (is_etf=true, zero holdings). It also states the ordering ('heaviest first'), which is useful behavioral detail.

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?

The description is two sentences plus a parenthetical, with no redundant words. It front-loads the primary purpose and adds necessary edge case details efficiently.

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?

Given the tool's simplicity (2 params, no annotations, no output schema), the description covers key edge cases and distinguishes the tool from related functionality. It does not explicitly describe the internal structure of holdings, but it is clear enough for an agent to understand the tool's purpose and behavior.

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%, with both parameters fully described in the input schema. The description adds no additional parameter semantics beyond what the schema already provides, so the baseline score of 3 applies.

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?

The description states a clear verb+resource: 'Get an ETF's constituent holdings and their weights, heaviest first.' It distinguishes from sibling tools by focusing specifically on ETF holdings, and clarifies the is_etf edge cases.

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?

The description explicitly warns against using this tool for reverse lookups ('which ETFs hold NVDA') and directs to a scan filter on the etf_holders column, providing an alternative. It also details when to expect empty holdings, giving clear usage context.

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