Fetch one illustration

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

With no annotations, the description carries the full burden. It discloses that the tool returns one image at a time and requires a previously created set, which is useful behavioral context. However, it does not mention potential errors, image format, or side effects (which are likely none), so it is not fully comprehensive but adequate for a simple read operation.

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 long, front-loaded with the core purpose, and every word earns its place. It conveys purpose, usage context, and a key behavioral trait without redundancy.

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 no output schema, the description explains the return value ('rendered image') and the intended workflow ('after create_illustrations', 'one at a time'). It is complete for a straightforward fetch tool, but could add details like image format or error handling for exceptional cases. Overall, it provides sufficient context for an agent to use 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?

Schema description coverage is 100%, with both parameters (setId and index) clearly described in the schema. The tool description adds minimal new meaning beyond reinforcing that the set was created by create_illustrations and that index refers to an illustration within that set. Baseline 3 applies because the schema already documents the parameters sufficiently.

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 the tool returns a rendered image for one illustration from a previously created set. It uses a specific verb ('Return') and resource ('rendered image for one illustration'), and distinguishes itself from siblings create_illustrations and regenerate_illustration by focusing on fetching a single item rather than creating or regenerating.

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 gives explicit usage context: the viewer calls this after create_illustrations, and it is used per illustration so that a single tool result never carries the whole set. This implies the correct workflow and differentiates from batch operations, though it does not explicitly mention when not to use it or compare to regenerate_illustration.

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