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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds that data comes from the official exchangeInfo endpoint, which is useful context but not a behavioral trait beyond that. It does not describe pagination or any other operational detail, so a 3 is appropriate.

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?

A single, well-structured sentence that front-loads the core action and scope, with no unnecessary words. Every part earns its place.

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 an output schema present and only one optional parameter, the description fully captures what the tool does. An agent can confidently call it knowing exactly what to expect in the response and what inputs are allowed.

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?

The schema provides 100% coverage of the single 'category' parameter, including an enum and description. The description's mention of US, HK, KR, CN stocks and commodities aligns with the enum values but does not add new semantics beyond what the schema already documents. Baseline 3 is correct.

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 clearly states the action ('Lists'), the specific resource ('Binance USDⓈ-M perpetuals'), and the scope (US, HK, KR, CN stocks plus commodities). It also cites the official exchangeInfo endpoint, making the purpose unambiguous and distinct from siblings which cover costs, referrals, fees, or news.

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 makes it obvious when to use this tool (to get a list of these perpetuals) and none of the siblings overlap, so there is no confusion. However, it does not explicitly mention any exclusions or alternative tools, but that is not necessary given the clear scope.

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