gemini_generate_image

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

With no annotations, the description must carry the full burden. It discloses that images are saved to assets/images and returns a human-readable summary listing file paths, which is useful. However, it omits details about overwrite behavior, file format, error handling, or authentication requirements, leaving gaps in behavioral transparency.

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 front-loaded with the main purpose and structured into Args/Returns sections. It is scannable and includes only necessary detail about model override, though the model note adds a bit of length. Overall, it is appropriately sized and well-organized.

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 no annotations and no visible output schema, the description covers the primary action and return value but misses contextual details like failure handling, file extension behavior, and permission or API key prerequisites. It is adequate for the main happy path but not fully comprehensive.

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%, and the description effectively compensates by explaining all three parameters: prompt as text description, model with default from environment and newer option, and filename as optional base filename without extension. This adds meaningful context beyond the schema's bare types and defaults.

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 states 'Generate an image with Google Gemini (Nano Banana) and save to assets/images', which is a specific verb+resource+destination. The mention of 'Google Gemini (Nano Banana)' clearly differentiates it from the sibling openai_generate_image, and 'image' distinguishes it from gemini_generate_video.

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 clearly implies this tool is for Gemini-based image generation, but it does not explicitly name alternatives or provide when-not-to-use conditions. It does include usage guidance via the model override option and default from environment variables, giving clear context without exclusions.

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