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

The annotations already declare the tool read-only and open-world; the description adds meaningful operational details: median-across-venues methodology, spread inclusion, USD denomination, and a $0.02 per-call fee in USDC on Base via x402. No contradiction with the annotations exists.

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?

Three short sentences each carry distinct value: what the tool provides, when to use it, and what it costs. The information is front-loaded and there is no filler or redundancy.

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 tool with one optional parameter and no output schema, the description covers the input, use cases, cost, and the core output concept of median price plus spread. It does not specify the exact response format, but an agent still has enough context to invoke and interpret the tool correctly.

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 already documents the single parameter symbols fully, including comma-separated format, max length, up to 20 values, example, and default BTC. The description adds no parameter-specific meaning, so the baseline score applies.

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 precisely specifies what the tool returns: an asset's USD value as a median across venues, with spread, explicitly contrasting it with a single exchange's last trade. This clearly distinguishes the tool from sibling market-data tools and makes its scope unmistakable.

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 gives concrete use cases: quoting, comparing venues, and spotting dislocated markets. It does not explicitly name alternatives or exclusion conditions, but the intended usage context is clear enough for an agent to decide when to call it.

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