run_lighthouse

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

No annotations are provided, so the description carries the full burden. It only lists what is returned but does not disclose behavioral traits such as audit duration, rate limits, required permissions, or whether the audit is run server-side or locally. This is insufficient for a tool that likely has performance and cost implications.

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 a single, front-loaded sentence that efficiently conveys the tool's purpose without unnecessary words. Every part contributes meaning.

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 two-parameter tool, the description covers the main purpose and outputs. However, given no output schema and no annotations, it could mention the structure of results or any side effects. The lack of behavioral context (e.g., potential delays) makes it merely adequate.

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% with basic descriptions for both 'url' and 'strategy'. The description echoes the enum values ('mobile or desktop') but adds no extra semantic meaning beyond what the schema already provides.

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 action ('Run a Lighthouse audit'), the resource ('a URL'), and the outputs ('scores, Core Web Vitals lab data, and improvement opportunities'). It distinguishes from sibling tools like get_core_web_vitals or analyze_website by specifying a full 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 description implies the tool is used for a comprehensive performance audit but lacks explicit guidance on when to prefer it over siblings like compare_performance or generate_report. No exclusions or conditions are mentioned.

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