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

Annotations provide readOnlyHint=false and destructiveHint=false, but do not disclose the cost implications. The description explicitly warns 'COSTS CREDITS', which is valuable beyond annotations. However, no other behavioral details (e.g., credits amount, processing time) are given, so a middle score 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 exceptionally concise, with two sentences that pack essential information: the output, the cost warning, and the source constraint. Every word serves a purpose, and critical constraints are front-loaded.

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 4 parameters with 0% schema coverage and no output schema, the description is somewhat incomplete. It explains the source constraint but not project_id's role or what the output 'clean plate' means practically. The cost warning is helpful but more context on expected behavior is needed for a full picture.

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 0%, meaning the schema provides no descriptions. The description mentions that exactly one of generation_id, asset_id, or url must be used, which adds meaning, but it does not clarify the purpose of project_id or the relationship between the three source parameters. This partially compensates for the schema gap but leaves gaps.

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's purpose ('subject cutout') and its output (transparent PNG + clean plate), but it does not explicitly distinguish itself from sibling tools like get_cutout or expand_image, which could be confused for similar operations.

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 provides a key usage guideline: exactly one of generation_id, asset_id, or url must be provided, which is crucial. However, it does not explain when to use cutout versus alternatives like expand_image or restyle, leaving some ambiguity.

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