page_speed_audit

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

The readOnlyHint annotation already establishes this as a safe read operation, so the description does not need to repeat safety. The description adds useful context by naming the output areas (Core Web Vitals, performance score, opportunities), but it does not disclose behavioral traits like execution time, URL accessibility requirements, or rate limits. This is adequate but not rich.

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 extremely concise: a one-line summary followed by a clear Args block. Every sentence earns its place, and the most important information is front-loaded. No unnecessary verbosity or repetition of schema 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?

For a simple read-only audit tool, the description covers the key purpose, primary parameters, and expected output categories. Since there is no output schema, the description's mention of Core Web Vitals, performance score, and opportunities provides sufficient completeness for an agent to select and invoke the tool. It does not delve into detailed return formatting, but that is not essential for this use case.

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 0% description coverage, so the description must carry the burden. It clearly explains 'url' (full URL to audit) and 'strategy' (desktop or mobile with default), adding value over the bare schema. However, the 'config' parameter is not mentioned at all, leaving its purpose and format undocumented. This gap prevents a higher score.

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 audits a page's loading performance with a specific verb ('Audit') and resource ('page's loading performance'), and lists distinct output categories (Core Web Vitals, performance score, opportunities). This differentiates it from sibling SEO audit tools like technical_seo_audit or on_page_audit, which focus on broader SEO factors rather than page speed.

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 when to use this tool (when you need to evaluate page loading performance), but it does not explicitly state when to use it over alternatives or mention any exclusions. No direct comparison to sibling tools such as on_page_audit or site_crawl is provided, leaving the agent to infer appropriate usage from context.

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