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

Annotations already establish readOnly, non-destructive, and closed-world behavior, but the description adds substantial context beyond them. It documents error behaviors for unknown and ambiguous ids, announced-id behavior, which fields are included, and when price history is available.

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 front-loaded with the core purpose, then moves to usage, return shape, error cases, and unit details. Every sentence adds operational value for a tool without an output schema.

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 no output schema and a read-only lookup, the description supplies the missing return and error context. It covers normal output, ambiguous and not-found cases, announced assets, units, and history conditions, leaving no major gaps.

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 coverage is 100%, so the parameters are already documented. The description still adds useful meaning: the id may come from an ambiguous result, shared tickers return matching ids, history is newest-only and only when price is published, and price history units are USD per token.

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 the resource precisely as "One published asset, with per-chain supply and an optional daily price history," which clearly identifies a single-asset lookup. It also distinguishes this from sibling list_assets by saying to call it after list_assets or when the id is already known.

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 explicit usage conditions: after list_assets, when the id is known, and when resolving an ambiguous result. It also warns not to guess among assets that share a display ticker, which is a clear exclusion case.

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