describe_image

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

With no annotations, the description carries the transparency burden. It discloses accepted input formats (local paths or public https URLs), the ability to handle multiple images, and gives advice on specificity. It does not mention limitations like file size or access restrictions, but the disclosed details are meaningful and go beyond a simple operation statement.

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 and front-loaded: a clear one-sentence purpose, a 'Useful for' bullet list, then an Args section. Every sentence adds value, and the example question is practical rather than filler.

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?

The tool is simple (2 params, no nested objects) and the description covers purpose, use cases, and parameter semantics. An output schema exists, so not detailing return values is acceptable. The description fully equips an agent to decide when and how to invoke the tool.

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 fully compensate. It does: 'images' is explained as local file paths or public https URLs, and 'question' is explained with guidance to be specific, including a concrete example. This adds substantial meaning beyond the raw schema.

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 uses a specific verb+resource phrase: 'Look at one or more images and answer a question about them.' It clearly distinguishes from siblings (generate_image creates images; list_models and set_api_key are unrelated) and provides concrete example use cases like reading screenshots and comparing images.

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 context for when to use the tool: it provides vision to a text-only model and lists several useful scenarios (reading text, describing photos, checking generated images, comparing images, extracting chart data). It does not explicitly name alternatives or state when not to use it, but the context is sufficient given the sibling tools.

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