Url Timing

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive. The description adds critical behavioral details: no JavaScript execution, no access control bypass, rejection of SSRF-sensitive URLs, and cache reuse behavior. This fully complements the annotations without contradiction.

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 with three sentences, each adding essential information. No redundant or vague language. Front-loaded with the core purpose, then usage constraints, then parameter guidance.

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 tool has an output schema (not shown but present), only 2 parameters with clear descriptions, and annotations covering safety and idempotency, the description is complete. It covers purpose, usage constraints, parameter behavior, and context without gaps.

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 100%, so baseline is 3. The description adds significant value by explaining the 'url' must be an absolute public HTTP(S) URL and elaborates on the 'fresh' parameter's semantics for cache behavior, going beyond the schema's brief descriptions.

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 returns measured end-to-end fetch timing for HTTP(S) resources. It distinguishes itself from sibling tools by focusing specifically on timing measurement, not other URL properties.

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 use only for public HTTP(S) resources, clarifies it does not execute JavaScript or bypass access controls, and provides guidance on the 'fresh' parameter: keep false for cache reuse, set true only when necessary. This helps the agent decide when to use this tool versus alternatives.

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