Describe Image (Nano Banana Pro)

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

The description discloses that the tool returns a text description and does not generate images, but it does not mention other behavioral traits such as read-only nature, authentication needs, or rate limits. With no annotations, this is a moderate disclosure.

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 concise (two sentences) and front-loaded with the primary action. Every sentence serves a purpose: stating the action and model, clarifying output, and specifying the default model.

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 straightforward image description tool, the description covers the essential purpose and output. However, with many siblings, more context on differentiation could improve completeness. The presence of an output schema reduces the need for return value details.

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 baseline is 3. The description itself does not elaborate on parameters; all parameter details are already in the schema. No additional meaning is added.

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 action ('analyze and describe') and resource ('images'). It specifies the method (Google Gemini image models) and explicitly notes that no image is generated, preventing confusion with generation tools. The default model is also mentioned, adding specificity.

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?

No guidance is given on when to use this tool versus siblings like 'analyze_image' or 'extract_structured_data'. The description lacks context for appropriate usage scenarios or alternatives, leaving the agent without decision support.

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