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

Annotations already declare readOnlyHint=true and openWorldHint=true, which the description does not contradict (no contradiction). The description adds valuable behavioral context: it indicates that this tool is useful for anomaly detection by comparing price differences across exchanges, a nuance not captured in annotations. It doesn't detail rate limits or data freshness, but given the annotations, this is adequate.

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 a single concise paragraph with three focused sentences: what it returns, applicability, and an example of use case (anomaly detection). No filler, and the most important information is front-loaded.

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 simple tool with one parameter and a clear return concept, the description fully covers the operational context. It explains why the tool exists and provides an example use case, which is sufficient for agent decision-making. No output schema exists, but the tool's output is implied by the description ('exchange + price + weight'), so no further detail is necessary.

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% (the schema fully describes the 'symbol' parameter with expected format and example). The description does not add further parameter-level meaning beyond what schema provides, such as additional constraints or usage notes for the symbol. Baseline 3 is appropriate because schema covers everything.

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 that this tool lists spot exchanges, prices, and weights that compose the index price for a trading pair, and explicitly notes it applies to regular perpetual pairs, not just composite indices—distinguishing it from the similar binance_get_composite_index_info. The verb 'list' with concrete output elements (exchange, price, weight) makes the purpose specific.

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 provides clear usage context: it is used when needing the index constituents for a regular perpetual pair, but does not explicitly mention alternatives or when not to use it. Since it contrasts with composite index info, an implicit hint is there, but no explicit 'when-not' or alternative tool names are given.

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