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

Annotations provide only false hints (readOnly, destructive, idempotent) which offer little guidance. The description adds the output format (transparent PNG) and implies a mutation (cut-out) but does not disclose side effects like whether the original is altered, async behavior, or any rate limits. Some value is added, but major behavioral aspects remain uncovered, so a mid 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: two sentences with the primary function first and alternatives listed in backticks. Every word contributes meaning; no filler or redundancy. It is front-loaded and structured for quick scanning.

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 tool with 2 required-or-optional parameters and no output schema, the description covers the core function and alternatives but omits parameter semantics and any prerequisites (e.g., authentication, required format of creationIdentifier). Given the low complexity, it is not fully complete but not disastrously lacking, so a 3 is fair.

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% for the two parameters, and the description does not explain `creationIdentifier` or `folderReference` at all. Without any parameter explanation, the agent cannot infer what to pass in. The description must compensate for the lack of schema descriptions but fails to, thus a score of 1.

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 function: 'Cut-out subject on transparent PNG' – a specific verb-resource pair (remove background to produce transparent output). It also distinguishes from alternatives by naming `images_color_background` and `images_generate` for different background treatments, so siblings are differentiated.

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?

Explicit when-to-use guidance: it says to use this tool for transparent PNG cutouts, and points to `images_color_background` for color backgrounds and `images_generate` with a prompt for AI scenes. This directly tells the agent when not to use this tool, making the usage context unambiguous.

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