performance.evaluate

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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint. The description adds context that it uses Playwright PerformanceObserver, returns a score/grade/recommendations, and mentions optional improvement recommendations, which 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 two sentences: first defines purpose and method, second describes output. Every word is essential, no redundancy. Perfectly front-loaded.

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 no output schema, the description covers return format (score, grade, recommendations). It explains the evaluation metrics and optional details. Could mention error handling or limitations, but sufficient for the complexity of a performance evaluation tool.

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 description coverage is 100%, so the description adds value by explaining the tool's purpose and output format (score 0-100, grade, recommendations), which helps agents understand what parameters like include_details affect. The description enriches the semantics beyond the schema's field-level 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 specifies the tool evaluates web page performance using Core Web Vitals (LCP, FID, CLS, INP, TTFB) via Playwright PerformanceObserver API, and returns a score, grade, and recommendations. This clearly distinguishes it from siblings like accessibility.audit or quality.evaluate.

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 this tool is for performance evaluation but does not provide explicit guidance on when to use it versus other sibling tools like quality.evaluate or page.analyze. No when-not-to-use or alternative suggestions are given.

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