download_image

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

Without annotations, the description covers key behaviors: conversion to WebP, optional resizing, default output directory, overwrite parameter, and the Unsplash requirement. It does not explicitly mention side effects like network requests or file system writes, but these are implied. A higher score would require explicit mention of non-destructiveness or rate limits.

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 concise and well-structured. It opens with the main action and result, then adds important constraints and guidelines. Every sentence adds value without 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?

Given no output schema, the description explains the return value (relative path for <Image src>). It covers all major aspects: source URLs, conversion, resizing, quality, naming, and overwrite behavior. The tool's purpose and usage are thoroughly described for an agent.

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 baseline is 3. The description adds value beyond the schema: clarifies the filename should be kebab-case, maxWidth resizes down only, outputDir default is public/images, and trackDownloadUrl is required for Unsplash. This provides useful context.

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 tool downloads an image, converts it to WebP, optionally resizes it, saves it in the project, and returns a relative path. It distinguishes from siblings by specifying it works with URLs from search_images and mentions the accepted sources.

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?

Explicitly states when to use the tool: after search_images, and only for URLs from pexels.com, unsplash.com, and pixabay.com. Also specifies that trackDownloadUrl must be passed for Unsplash results, providing clear prerequisites.

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