Compose Multiple Images with Nano Banana Pro

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

Annotations already provide readOnlyHint=true and destructiveHint=false, indicating a safe read operation. The description adds valuable behavioral context beyond annotations by specifying image limits (up to 14 total, with breakdowns for objects and humans), which helps the agent understand constraints. It doesn't mention rate limits, authentication needs, or processing time, but adds meaningful operational context.

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 clear sections (purpose, use cases, limits, args, returns, examples) and front-loaded key information. It's appropriately sized for a complex tool, though the 'Args' and 'Returns' sections could be more concise since they largely repeat schema information.

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 tool's complexity (5 parameters, image processing), the description provides good context with use cases, limits, and examples. While there's no output schema, the 'Returns' section adequately documents the response structure. The description could benefit from more guidance on prompt engineering or error handling, but covers most essential aspects.

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 by briefly mentioning the 'images' array structure and model requirement, but doesn't provide additional semantic context or usage examples for parameters beyond what's in the schema descriptions.

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 ('compose new images', 'transfer styles', 'maintain character consistency', 'combine objects') and resources ('multiple reference images', 'Nano Banana Pro'). It distinguishes from sibling tools by focusing on multi-image composition rather than editing single images, generating from scratch, or listing models.

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 through the bullet points of use cases (group compositions, style transfer, character consistency, object combination) and the limits section specifying image type constraints. However, it doesn't explicitly state when NOT to use it or name specific alternatives among the sibling tools.

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