download_image

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

As no annotations are provided, the description carries the full burden of behavioral disclosure. It clearly explains return modes (file path or base64), the important relative-path resolution behavior tied to the server's cwd, and default size behavior. This is meaningful context beyond basic write intent, though error handling and permissions are not covered.

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 with clear Args, Returns, and Example sections. The relative-path warning is essential and the example adds practical value. Every sentence contributes, with no fluff 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 moderately simple tool, the description covers parameter details, return type, and a concrete example. The absence of error handling and explicit tool-selection guidance is a minor gap, but the information provided is sufficient for typical usage, especially given the output schema exists.

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?

Despite the input schema having 0% description coverage, the description thoroughly documents all three parameters: image_id format with an example, size options with valid values, and output_path with a critical warning about absolute versus relative paths. This fully compensates for the schema's absence of descriptions.

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 'Download an image to local storage or return base64 encoded data,' using a specific verb and resource. This distinguishes the tool from sibling tools like search_stock_images and get_image_details.

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 provides usage details for parameters but does not explicitly state when to use this tool versus alternatives. The intended use is implied by the tool name and purpose, but no explicit when-to-use or when-not-to-use guidance is given.

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