generate_images

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It effectively describes key behaviors: images are auto-saved to outputDir, returns an array of file paths, includes cost (~1,290 tokens per image), and adds a SynthID watermark. It also covers models and aspect ratios, though it lacks details on error handling or rate limits.

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 well-structured with sections like CAPABILITIES, MODELS, WORKFLOW, and RETURNS, making it easy to scan. It is appropriately sized, but some sentences could be more concise, such as the workflow steps which are somewhat verbose. Overall, it front-loads key information efficiently.

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 complexity of the tool (7 parameters, no output schema, no annotations), the description is largely complete. It covers purpose, usage, behaviors, and returns, though it could benefit from more detail on error cases or output structure. The absence of an output schema is partially compensated by describing the return as an array of file paths.

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 100%, so the schema already documents all parameters thoroughly. The description adds minimal value beyond the schema, such as mentioning that inputImageUri is for editing and outputDir has a default, but does not provide significant additional semantics or usage examples for the parameters.

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 with specific verbs ('generate or edit images') and resources ('images using Gemini image models'), distinguishing it from sibling tools which focus on batch operations, file management, and chat. It explicitly lists capabilities like text-to-image generation and image editing, making the purpose 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 provides clear context for when to use this tool, such as for text-to-image generation or editing existing images, and outlines a workflow with optional parameters. However, it does not explicitly state when not to use it or name alternatives among sibling tools, which are unrelated to image generation.

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