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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered. The description adds nothing beyond that on behavior — no error handling for unknown ids, no note that the image is a 2,500 px asset served how, no auth or rate-limit context. With annotations carrying the load, a 3 is appropriate.

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?

A single front-loaded sentence with zero filler; the id-based scope and the payload contents are delivered immediately without repetition of the title or annotations.

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 correctly takes on the burden of telling the agent what comes back, listing the eight payload elements. It stops short of describing the shape or types (e.g., whether the 2,500 px image is a URL or binary, whether museum record is a link), which is a minor remaining gap for a tool with no schema.

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%, and the schema even supplies an example value ("aic-56905"), so the parameter is fully documented in structured data. The description only restates 'by its Artnap id' without adding format or sourcing guidance, 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 names a specific verb (retrieve one artwork) and resource, scoped by 'its Artnap id', and enumerates the returned fields (title, artist, year, museum, license, image, page, museum record). That makes it clearly distinct from the sibling 'search_artworks' (plural/multi-result) and the list_* tools, though it never names 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 rather than stated: 'by its Artnap id' tells the agent this is a direct-key lookup, which contrasts implicitly with search_artworks. There is no explicit 'use this when you already have the id' instruction or warning that the id must be obtained elsewhere first, so the agent must infer the selection rule.

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