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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context: it accepts three different identifier forms and resolves object numbers for the caller, and it is keyless (no API key needed). It also gives a concrete example of the return value. It doesn't mention rate limits or error behavior, but for a read-only lookup tool this is adequate.

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 compact and front-loaded: it opens with what the tool returns, then the accepted inputs, then the keyless note, then a concrete example. Every sentence earns its place. The example is particularly valuable because it anchors the abstract input forms to a well-known object.

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 read-only single-object lookup with no output schema, the description covers the essential information: what fields are returned, what inputs are accepted, and how identifiers are resolved. The only minor gaps are the absence of error behavior (e.g., what happens with an invalid id) and rate limits, but these are not critical for a keyless read-only tool. The example and field enumeration make it complete enough for an agent to call 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?

Schema description coverage is 100%, so the schema already documents both parameters. The description adds value by explaining that the id parameter can be a numeric id, a URI, or an object number, and that object numbers are resolved automatically. It also clarifies the relationship between id and object_number (alias). This goes beyond the schema's own description, which lists the same forms but doesn't emphasize the resolution behavior.

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 verb ('Accepts', 'resolved for you') and resource ('One Rijksmuseum object in full'), enumerating the exact fields returned (title, maker, date, object type, materials, place, depicted subjects, curatorial description, object number, rights statement, image URL). It also distinguishes itself from siblings by naming the input forms and giving a concrete example (The Night Watch). This is unambiguous and clearly differentiates from rijks_search and rijks_object_image.

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 clearly states when to use this tool: when you need a single object's full details. It also explains the accepted input formats (numeric id, URI, or object number) and notes that object numbers are resolved automatically. It doesn't explicitly say 'use rijks_search for finding objects' or 'use rijks_object_image for images only', but the sibling names and the description's scope make the usage context clear. A small gap: no explicit exclusion of when not to use it.

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