Analyze Image

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

With no annotations provided, the description carries full behavioral burden and does so excellently. It discloses output modality, the default model, the server-side max_tokens allocation behavior, the Gemini 3 thinking-token pitfall that can mimic a timeout, and a recommended timeout value. This is genuine transparency beyond what the schema provides.

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 purpose, then provides output modality, model default, a critical warning, and a timeout recommendation in only four sentences. Every sentence earns its place; there is no filler or redundancy.

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 5-parameter tool with a 100% documented schema and an output schema, the description is complete enough. It covers what the tool does, what it returns, the default model, the critical max_tokens constraint, and timeout expectations. The structured schema and output schema handle parameter details and return values, so the description does not need to repeat them.

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 coverage is 100% with detailed per-parameter descriptions, so the baseline is 3. The description adds value by explicitly warning against setting max_tokens and explaining why ('a small cap is spent on Gemini 3 thinking and returns empty output that looks like a timeout'), plus pointing out the default model. This elevates it above the schema-only baseline.

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 opens with a specific verb and resource: 'Analyze and extract information from one or more images using Gemini multimodal understanding.' It also clarifies the output type ('Returns a text analysis - no image is generated'), which distinguishes it from image-generation siblings like generate_image. This is a clear, non-tautological statement of 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 gives clear use context: analyze/extract information from images and produce text output, not an image. It also provides critical operational guidance such as omitting max_tokens, the default model, and a recommended timeout. However, it does not explicitly name alternative tools like describe_image or state when NOT to use this tool versus those siblings, so it falls just short of a 5.

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