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

The description adds important non-obvious behavior beyond the annotations: return format (image URLs), provider defaults, image count, and especially the billing model with and without an API key. It does not contradict readOnlyHint; generating an image is not mutation of existing state, and the cost disclosure is a valuable side-effect warning.

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 usage trigger, and every clause contributes use cases, output, or pricing. The long sentence with nested clauses is slightly dense but not padded.

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, this description covers the essential invocation context: when to use it, what it returns, provider/count choices, and cost. The remaining parameters, such as aspect_ratio and quote, are already fully described in the schema.

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?

With 100% schema coverage, the schema already documents all parameters. The description restates provider, quality, and count options but adds little new parameter-level meaning beyond the SWOGE prompt guidance and output-format note.

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 opens with a clear action and object ('Use this when you need an image'), then enumerates concrete use cases: illustration, meme, post visual, and the SWOGE character. This clearly distinguishes it from the generate_video sibling without requiring schema inspection.

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?

'Use this when you need an image' gives an explicit trigger condition, supported by relevant examples. It does not explicitly name alternatives or say when not to use it, so it stops short of a full routing guide.

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