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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, closed-world), so the bar is lower. The description still adds real value by disclosing the no-fabrication contract: it 'refuses, and estimates nothing' when no comparison is published, plus what the response content will be.

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?

Purpose is front-loaded and every clause carries information (scope, band definition, output content, input example, refusal behavior). The parenthetical band definition and dense run-on structure make it slightly harder to parse than ideal.

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?

For a read-only, one-parameter tool with no output schema, the description is largely complete: it explains what is compared, what is returned, and the failure mode. It is only mildly deficient in not clarifying tool selection relative to its benchmark siblings.

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 0% for the single ticker parameter, so the description must carry the load. It provides a concrete example ('such as AOR') which conveys expected format, but does not state constraints such as whether the ticker must be an allocation ETF with a published band.

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 specific comparison operation (an allocation ETF vs. the ETFIQ benchmark for its band) and enumerates the return content (total returns by window, the difference, risk and cost). It distinguishes itself in substance from siblings like get_benchmark, though it never names them explicitly, so it falls short of the top band.

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?

It gives partial usage guidance via the input hint ('Takes a ticker such as AOR') and one explicit when-not case (refuses when ETFIQ has not published a comparison). However, it never says when to choose this tool over get_benchmark/list_benchmarks, leaving the agent to infer the route.

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