describe_image

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

With no annotations, the description carries the full behavioral burden. It discloses the core behavior, accepted formats, and input source types, but does not mention output specifics, error behavior, size limits, or network implications when fetching URLs. This is adequate but not rich.

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 two concise sentences with no filler. Essential information—purpose, model, formats, and input types—is front-loaded, making it easy for an agent to parse quickly.

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 simple two-parameter tool with full schema coverage, the description provides enough context for an agent to invoke it correctly. The only minor gaps are unspecified constraints like file size limits or behavior on inaccessible URLs.

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 both parameters. The tool description adds minimal semantic value beyond the schema—it restates the image path/URL constraint but does not elaborate on the prompt parameter or its effect.

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 states a specific action ('Convert an image... into a text description'), identifies the vision model as the mechanism, enumerates supported formats, and clarifies accepted source types. This makes the tool's purpose unambiguous and distinct from the sibling 'configure'.

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 the tool is appropriate: whenever an image needs to be described as text. It also provides practical input constraints (JPEG/PNG/GIF/WebP, local path or http(s) URL), but does not explicitly discuss exclusions or compare against alternatives.

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