browser_performance_check

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

No annotations exist, so the description carries full burden. It details the output structure, error conditions (browser not launched, invalid budget), and the scope (current page). It does not mention side effects, but performance collection is generally safe.

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 verbose due to bilingual content, with some redundancy (Chinese repeats English info). However, it is well-structured with an opening summary, then detailed Chinese bullets. Could be more concise.

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's complexity (3 params, nested objects, no output schema), the description covers purpose, usage, output format, parameter details, errors, and an example. This is complete enough for agent invocation.

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%, and the description adds value by providing defaults for slowRequestMs and sessionName, a detailed breakdown of budgets fields, and an example. This enriches understanding beyond the schema.

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 it collects page performance metrics and evaluates against budgets, listing specific metric types (navigation, paint, resource, long task, CLS/LCP) and Core Web Vitals. This distinguishes it from sibling tools like browser_performance_trace or browser_lighthouse_audit.

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 Chinese section explicitly lists use cases: pre-launch baseline, CWV compliance, slow request/long task localization, budget gate checks. While it doesn't state when not to use, the context is clear and no alternatives are mentioned.

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