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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so safety is covered. The description adds value beyond annotations with the explicit statement 'The server returns URLs, not image bytes' and the detailed list of return fields, which helps the agent understand the exact shape of the response without an output schema.

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 two sentences, front-loaded with the primary action and resource, immediately followed by a useful caveat about URLs. Every word adds value; no redundant or filler content.

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 simple get-by-id tool with a single parameter and no output schema, the description provides all necessary context: resource type, specific return fields, and the behavior regarding image bytes. The sibling list suggests this is part of a family of similar getters, and the description is sufficiently complete for an agent to invoke it 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 has one parameter, image_id, with no description coverage. The description's phrase 'by id' adds minimal context, implying image_id is an identifier, but it does not explain what kind of id (database key, API id) or how to obtain it. For a simple single parameter, this is adequate but leaves room for more clarity.

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 clearly states 'Get one photograph by id' and enumerates the specific fields returned (title, photographer, capture date, place, coordinates, subjects, rights, IIIF manifest, image_url). This makes the purpose unambiguous and distinguishes it from sibling tools like get_audiovisual or get_document that target different resource types.

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 implies usage when you have a photograph id and need its metadata. It also provides an important exclusion: 'The server returns URLs, not image bytes,' guiding agents away from using this tool to download image data. However, it does not explicitly name alternative tools for byte retrieval or searching.

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