render-instance-frame

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

The description discloses that the tool returns 'the rendered image as a base64-encoded string', which is critical behavioral info. No annotations are provided, so this description carries the full burden, and it adequately informs about the output format without contradictions.

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, directly stating the function and prerequisites. Every sentence adds necessary information without redundancy or fluff.

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?

Given the straightforward nature of the tool and full schema descriptions, the description covers the returned output format and required inputs. It doesn't discuss error handling or performance, but that's acceptable for a simple rendering 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?

The input schema has 100% description coverage, with each parameter's purpose already explained (e.g., 'DICOM Study Instance UID'). The description only mentions the UIDs and frame number generically, adding no significant new meaning beyond the schema.

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 'Renders a specific frame from a DICOM instance to an image format', specifying the resource (DICOM instance frame) and action (render). It distinguishes from sibling tools like find-instances (which retrieves UIDs) and get-instance-metadata (metadata retrieval).

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 instructs that Study, Series, and SOP Instance UIDs are required and that they come from find-instances. It also mentions the frame number. While it doesn't explicitly state when not to use the tool, the context is clear enough for typical use.

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