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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and non-destructive, so the safety profile is covered. The description adds real behavioral context about the result: it returns typical price, the middle half of prices, and price per square inch, drawn from independent artists' shops and comparable works - which is consistent with openWorldHint=true and tells the agent what kind of estimate it gets.

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?

Two sentences that are front-loaded with the purpose and then the output detail; the second sentence is list-shaped but every clause (typical price, middle half, price per square inch, source) earns its place. No redundant restatement of the name.

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?

There is no output schema, so the description carries the burden of describing the return values and does so well (typical price, interquartile range, per-square-inch). With 100% parameter coverage and full annotation coverage, nothing critical is missing for a read-only lookup tool.

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%, so all six parameters (including the kind and unit enums and the original/print flag) are already documented in the schema. The description echoes 'size and medium' and 'original work or prints' but adds no format or default detail beyond what the schema provides, so baseline 3 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 states a specific resource (fair price for a new artwork) and the two dimensions it keys on (size and medium), and it explains what is being measured against (comparable works in independent artists' own shops). This clearly separates it from sibling pricing tools like price_commission or calculate_resale_royalty, though it does not name those siblings explicitly.

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?

Usage is implied by 'fair price for a new artwork by size and medium' - an agent can infer this is for pricing a not-yet-sold work. However, there is no explicit when-to-use/when-not-to-use statement and no routing to the related siblings (price_commission, compare_where_to_sell, calculate_resale_royalty).

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