PageSpeed analysis

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

The description discloses the runtime (10-30s) and that it combines Lighthouse and real-user data, going beyond the readOnly annotation. It implies no side effects, consistent with the annotations, and provides useful operational context.

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: what it does, what it returns, when to use, and runtime. It packs essential information without fluff or 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?

The description covers purpose, output summary, usage context, and runtime, making it complete for an agent to decide and call. It provides a clear summary of the output schema without needing to enumerate every field.

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 description clarifies the strategy parameter with its default ('mobile') and explains the rationale ('most paid traffic'), adding meaning beyond the bare schema. The url parameter is self-explanatory and needs no further elaboration.

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 runs PageSpeed Insights for a landing page, returning performance scores, lab/field data, and opportunities. It explicitly ties usage to ad final URLs, making the purpose distinct and actionable.

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?

It explicitly says to use on ad final URLs because slow landing pages depress Quality Score and waste paid clicks, giving clear when-to-use guidance. The mention of strategy default and runtime further supports proper usage.

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