analyze_performance

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

With no annotations, the description carries the full burden. It discloses the outputs (LCP, FCP, CLS, etc.) and that it runs Lighthouse, but does not mention side effects, auth requirements, rate limits, or destructive potential. It is sufficient for a read-only analysis but lacks detail on behavioral traits like execution time or failure modes.

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?

Two sentences with no filler. The first sentence front-loads the key action ('Run Lighthouse on a URL') and output, the second lists specific metrics. Every sentence is purposeful and 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?

The description covers the main outputs but lacks details on execution context (e.g., time to run, caching, error handling). With no output schema or annotations, there are gaps such as how results are returned and potential limitations.

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% (all parameters described). The description adds no additional meaning beyond the schema – it does not clarify formats, defaults, or constraints. Baseline of 3 is appropriate as per guidelines.

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 runs Lighthouse on a URL and returns Core Web Vitals, metrics, and recommendations. The verb 'Run Lighthouse' and resource 'URL' are specific, and the output is detailed. It distinguishes itself from siblings like 'crawl_site' by focusing on a single page analysis.

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 no guidance on when to use this tool versus alternatives (check_threshold, compare_performance, crawl_site). There is no mention of context, prerequisites, or situations to avoid. The agent must infer usage from the purpose alone.

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