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

Annotations already establish read-only/idempotent safety, and the description adds useful behavior beyond that: parallel venue queries, OKX quoting USDT when USD is requested, and the cross-venue spread semantics. It does not reveal error handling or unsupported-pair behavior, but those are minor for a read-only ticker.

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?

Every sentence earns its place: returned data, execution behavior, OKX quote nuance, arbitrage use case, and cost. It is front-loaded with the most important output fields and stays compact despite covering several behavioral details.

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 single-parameter read-only tool with no output schema, the description is complete enough to invoke correctly: it lists all returned metric groups, venue behavior, the pair semantics, and cost. Nothing essential is missing.

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?

Input schema already covers pair with examples at 100% coverage. The description adds valuable parameter-related meaning by clarifying how 'USD' is interpreted on OKX (USDT) and by explaining that the pair is requested across three venues at once.

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?

States exactly what it returns (bid/ask/last, 24h change, volume, range) for a pair, names the three venues, and adds the cross-venue spread as a distinguishing feature. The 'Queries each venue's public ticker' sentence reinforces the verb, so it is clearly separable from price/price_history siblings.

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 conveys when to use it: when you need side-by-side multi-venue prices or want to spot arbitrage gaps via the cross-venue spread. It does not explicitly name alternatives or state when not to use it, so it stops short of a 5.

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