Nano Banana 2 Official

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

With no annotations, the description bears full burden. It discloses that the preset owns provider, model, timeout, retry, and dispatch behavior, and specifies override rules (preset + api_key required together). This adds significant behavioral context beyond the schema, though it could mention response modality handling or other traits.

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 four sentences, front-loaded with purpose. It is concise and covers key points without unnecessary detail, though the structure could be improved by separating purpose, configuration, and error behavior more clearly.

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 12 parameters and no schema descriptions, the description covers critical behavioral aspects (preset ownership, overrides) and references enums, but lacks details on mode (generate vs edit), prompt handling, save_path semantics, and output behavior. An output schema exists, but the description does not leverage it comprehensively.

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%, so the description must compensate. It only mentions image_size and aspect_ratio as coming from catalog enums, and that invalid size errors include preset list. The other 10 parameters (including required ones like prompt and save_path) are not explained, leaving significant gaps.

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 generates or edits images via a Gemini compatible gateway, which distinguishes it from GPT-based siblings like gpt_image_2_official. The verb 'Generate or edit' and the specific resource 'images' provide a precise purpose.

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 implies usage for Gemini-based image tasks and mentions override behavior, but it does not explicitly state when to use this tool versus alternatives (e.g., when to prefer GPT). No explicit when-not or exclusion guidance is provided.

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