download_image

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

With no annotations provided, the description carries full burden. It discloses key behaviors: downloads to temp directory, returns file path, and opens new tab for cross-origin images. However, it lacks information about error handling, file format support, permissions needed, or rate limits. The description doesn't contradict annotations since none exist.

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 reasonably concise with two main clauses. However, the second clause about opening new tabs could be more clearly integrated. The description is front-loaded with the core functionality.

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 tool with 4 parameters, 0% schema coverage, no annotations, and no output schema, the description is insufficient. It doesn't explain what the return value looks like beyond 'file path', doesn't cover all parameters, and lacks error scenarios or limitations. The cross-origin behavior is helpful but incomplete.

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 compensate. It mentions 'URL' which relates to 'image_url' parameter, but doesn't explain the purpose of 'session_id', 'output_filename', or 'timeout'. The description adds minimal value beyond what parameter names already suggest.

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 verb 'download' and resource 'image from URL', specifying it saves to temp directory and returns file path. However, it doesn't explicitly differentiate from sibling 'download_file' which appears to be a more general file download tool.

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 mentions 'it will open a new tab if the image is not from the same origin as the current page' which provides some behavioral context, but offers no explicit guidance on when to use this tool versus alternatives like 'download_file' or 'take_screenshot'. No prerequisites or exclusions are stated.

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