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

Annotations already declare destructiveHint=true, openWorldHint=true, and readOnlyHint=false, and the description does not contradict them. The description adds useful behavioral context by mentioning the 1-credit cost and sensitive-tier approval behavior. However, it does not disclose what is actually destructive—whether the original image is overwritten or a new asset is created—which matters for a tool flagged destructive.

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 compact and front-loaded with the core function, followed by routing and approval guidance. Every section serves a purpose. The approval note is slightly jargon-heavy ('the card is the yes'), but the overall structure is efficient and well organized.

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 6-parameter tool with no output schema, the description covers the main invocation triggers, credit cost, and approval process. The parameter details are left to the heavily annotated schema. It could be more complete by specifying the expected output location or which input source to prefer, but the combination of description and schema provides enough for correct invocation.

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 100%, so the input schema already documents all six parameters with specific descriptions. The tool description itself adds no parameter-level meaning, such as how image_url relates to artifact_id or which is preferred. The baseline of 3 is appropriate given full schema 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 states a specific operation: 'Remove the background from an existing image, leaving the main subject isolated on a transparent background (PNG).' This clearly identifies both the resource and the exact transformation, and the routing phrases reinforce the intended use. It is immediately distinguishable from image-generation siblings like generate_image_xai and vectorize_image.

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 'Routing' section explicitly lists trigger phrases ('isolate the subject', 'make background transparent', 'remove background') and directs the agent to use this tool for them. It also adds operational guidance about credit cost and the sensitive-tier approval flow. It does not explicitly describe when not to use it or name an alternative tool, so it stops short of a 5.

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