responsive_images

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

No annotations are provided, so the description carries the full burden. It clearly states the tool 'produces multiple size variants with proper HTML markup', implying a safe, read-only operation. However, it does not disclose whether external requests are made, the exact format of the returned HTML, or any side effects. 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, front-loaded with the main action ('Generate srcset and <picture> element HTML'), and contains no superfluous words. Every sentence contributes to understanding the tool's purpose and behavior.

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 7 parameters, no annotations, and no output schema, the description gives a solid overview: it states the main behavior (generating HTML), the input (base URL), and the output (markup). The schema documents parameter details, so the description is sufficiently complete, though a mention of the exact return type (e.g., string) would be slightly clearer.

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?

The input schema covers 100% of parameters with individual descriptions, so the description does not need to add much. It only references 'base image URL', which is already in the schema. No additional semantic value is provided beyond the 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 the specific verb 'Generate' with the resource 'srcset and <picture> element HTML', clearly distinguishing it from sibling tools like image_metadata, find_favicons, extract_og_image, and generate_placeholder. It exactly states what the tool does: produces responsive image HTML from a base URL.

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: use when you need responsive image markup with srcset and <picture>. It does not explicitly state when not to use it or reference alternatives, but the context is unambiguous and sufficient for a tool with this simplicity.

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