Analyze Multiple Pages

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

Annotations already declare readOnly, idempotent, and non-destructive behavior. The description adds meaningful context beyond annotations: it mentions progress notifications emitted when supported by the client and notes that results include success/failure counts. This gives the agent insight into execution behavior without contradicting annotations.

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 three sentences, each earning its place: purpose is front-loaded, followed by sibling routing, a practical example, and a behavioral note about progress notifications. There is zero fluff or redundancy, making it easy for an agent to parse quickly.

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 six parameters with complete schema documentation, a robust output schema, and annotations covering safety (readOnly, idempotent, non-destructive), the description provides all necessary guidance for correct invocation. It covers usage, alternatives, an example, and a behavioral note—comprehensive for this tool's complexity.

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 has 100% description coverage for all six parameters, including units, defaults, and constraints. The tool description adds no additional parameter-level guidance, but since the schema fully documents semantics, the baseline of 3 is appropriate. The description's mention of '1–10 URLs' aligns with schema constraints but adds no new information.

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: analyze 1–10 public URLs and return per-page results plus success/failure counts. It distinguishes itself from sibling tools by explicitly naming pagespeed_analyze_page for a single URL and pagespeed_compare_pages for direct comparison, making selection unambiguous.

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 provides explicit routing guidance: use pagespeed_analyze_page for one URL or pagespeed_compare_pages for direct comparison. It also includes a concrete example (triage ten highest-traffic landing pages) that grounds the tool in real usage, leaving no ambiguity about when to invoke it.

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