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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and destructiveHint, covering safety traits. The description adds 'public URL' as a requirement and lists what is measured, which is useful but not extensive. It does not disclose potential latency, rate limits, or failure modes.

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, front-loaded sentence with no redundancy. Every word contributes to understanding the tool's purpose and scope. It is appropriately concise.

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 simple tool with one parameter, good annotations, and an output schema, the description is reasonably complete. It covers the tool's function and key input constraint (public URL). It could mention potential limitations or performance implications, but these are not critical given the simplicity.

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 coverage is 0%, so the description must compensate. It adds that the URL must be public, which is a meaningful constraint beyond the schema's format. However, it does not elaborate on URL requirements or quirks, leaving some ambiguity.

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's function: measuring website response latency, payload size, compression, caching, and performance signals for a public URL. The verb 'Measure' and specific metrics distinguish it from sibling web tools like accessibility, SEO, or security audits.

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 implies usage for performance analysis but does not explicitly state when to use it over alternatives or provide exclusions. It gives clear context but lacks explicit 'when to use' guidance or mention of sibling tools.

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