Image generation

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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the description does not need to repeat that. It adds valuable cost disclosure ('Costs credits from the account wallet') not present in annotations. It does not mention output format or failure behavior, but given the simple generation task and annotation coverage, this is a minor gap.

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?

Three short sentences with no filler. The purpose is front-loaded, followed by use cases and cost. Every sentence adds value, and the structure is easy to scan.

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 simple tool with one required parameter, the description covers purpose, use cases, and cost. However, it lacks details on the output format (e.g., URL vs. base64) since there is no output schema, and it does not explicitly state that sufficient credits must be available. These gaps are minor given the tool's simplicity.

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 67%, and the description adds no parameter-specific details beyond what the schema already provides. It only implies the prompt is the input; style and aspectRatio are not mentioned. Since coverage is not high, the description could have compensated but did not, so it stays at the baseline of 3.

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 'A prompt → a production-ready image', which specifies the action (generate) and resource (image). It lists concrete use cases (marketing visuals, product scenes, brand imagery), and the sibling tools are all text-processing, so this tool's image-generation purpose is unambiguous.

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 clear context on when to use the tool (for marketing visuals, product scenes, consistent brand imagery). It does not explicitly state when not to use it or name alternatives, but the sibling list is dominated by text-processing tools, making the distinction implicit and sufficient for most agents.

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