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

Annotations already provide readOnlyHint, idempotentHint, openWorldHint, and destructiveHint which clearly indicate the tool is safe, idempotent, and makes external calls. The description adds only that URLs must be public and HTTPS, which is marginal additional context. No further behavioral traits (e.g., rate limits, timeouts) are disclosed.

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 a single, concise sentence that front-loads the key information: verb, object, and constraints. No wasteful words or redundant details.

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 the complexity of making external HTTP requests (openWorldHint) and the lack of an output schema, the description should provide more context on what 'response metadata' means, error handling for failed URLs, and how results are presented. The sibling tool is mentioned but no guidance on selecting between them is offered, leaving the description 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?

The input parameter 'urls' has no schema description (0% coverage) and the tool description does not explain its semantics beyond the general purpose. For a user, it is unclear what format of URIs are accepted or what 'response metadata' specifically includes, so the description fails to compensate for the lack of schema details.

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 'compare', the resource 'response metadata', and the target 'public HTTPS URLs' with a specific limit of up to five. It effectively differentiates from the sibling tool 'web_freshness' which likely handles a single 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 does not explicitly state when to use this tool over the sibling 'web_freshness'. The usage context is implied by the tool's name and the sibling list, but no direct guidance on when-not-to-use or alternatives is provided.

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