comfy_get_output_image

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 the return type (image content block) and the download aspect, but it doesn't disclose error handling, file availability, or network dependencies. This is consistent with annotations and adds a bit of context, so a 3 is appropriate.

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 extremely concise, with the main purpose stated in the first line and parameter details in a compact Args block. Every sentence adds value, and it is front-loaded with the key action and return type.

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 simple nature of the tool (two parameters, no output schema), the description covers the essential purpose and return type. It doesn't fully explain edge cases like missing files or nested subfolder behavior, but the annotations and simplicity mitigate the need for extensive documentation.

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 coverage is 0%, so the description must add meaning to the parameters. It provides an example filename and notes that subfolder is optional, which goes beyond the schema's bare type and title. However, it doesn't explain constraints, how to locate images, or relationship to other tools, so it's minimal coverage.

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 action ('Download an output image from ComfyUI') and the outcome ('return it as an image content block'). It distinguishes this from siblings like comfy_get_image_url (which returns a URL) and comfy_list_output_images (which lists images) by specifying the return format.

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 an actual image content block is needed, but it does not explicitly mention alternatives or exclusions. It lacks guidance on when to prefer this over comfy_get_image_url or comfy_download_batch, so the agent must infer the use case.

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