get_record_image

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

Annotations cover only read-only and open-world. The description adds genuinely useful behavioral context on top: it discloses the auth prerequisite ('Requires an access token') and the important negative-result behavior ('many records carry no image link at all, in which case this says so rather than inventing one'), plus what the payload contains (image/waypoint links, DGS and image numbers).

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 operative sentence is front-loaded, and the paragraphs on missing image links and the token requirement each carry functional weight. The 'persona is somebody's reading of the record' passage is more flavor than instruction and could be trimmed, but it does justify the verify-against-film usage.

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, the description steps in to describe the return shape (image/waypoint links, DGS and image numbers) and the common no-link case. Combined with the auth note, an agent has everything needed for a one-parameter read 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% and there is a single parameter, so the schema already documents 'ark' adequately. The description adds no format, encoding, or lookup nuance beyond the schema's 'Record ark or id', so the 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 opening sentence gives a specific verb and resource with the direction of the relationship baked in ('the document image an indexed record was taken from'), which is exactly what separates it from the reverse-direction sibling get_records_on_image and from the retrieval siblings get_film_image/download_image. An agent can tell what this returns without opening the schema.

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?

Clear context: use it to verify an indexed reading against the actual image ('anything that matters should be checked against the film'), and it tells the agent what to do when no image exists (read the citation, order the film). It stops short of naming alternative tools such as get_film_image or download_image, so there is no explicit when-not routing.

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