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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=true, and destructiveHint=false. The description adds the useful 'paid' caveat, which is not captured in annotations, but it does not disclose other behavioral traits like output format, rate limits, or failure modes. It does not contradict annotations.

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 very short and front-loaded with no filler words, which is concise. However, it is just a noun phrase with a parenthetical, not a complete sentence, and it sacrifices substance for brevity.

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?

There is no output schema, so the description needed to explain what the tool returns, but 'ETF holdings' alone does not specify whether it returns constituents, weights, prices, or other details. The 'paid' caveat is helpful, but overall the description is too sparse to be complete for a tool with no structured output definition.

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?

With schema description coverage at 0%, the description needed to explain the 'symbol' parameter but does not. The schema itself only provides a type and an example ('SPY'); the description adds no meaning about what symbol means, accepted formats, or how it relates to ETFs.

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, 'ETF holdings (paid),' names the resource but lacks a verb such as 'retrieve' or 'list' to specify an action. It is essentially a restatement of the tool title and does not explicitly clarify what the tool does beyond referring to ETF holdings data.

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?

No guidance is provided about when to use this tool, what prerequisites apply (e.g., a paid subscription), or how it differs from related sibling tools like key_metrics, quote, or profile. The description gives no context for choosing this over alternatives.

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