Server Quality Checklist

Tool Scores

• analyze_performanceA
  3.5/5.0
  Behavior3/5

  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.

  Conciseness5/5

  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.

  Completeness3/5

  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.

  Parameters3/5

  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.

  Purpose5/5

  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.

  Usage Guidelines2/5

  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.

• check_thresholdA
  4/5.0
  Behavior3/5

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

  No annotations are provided, so the description carries the burden. It mentions defaults use Google's 'poor' thresholds and that it only fails on genuinely bad metrics, but does not explain the return format or side effects (though likely read-only).

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  Two sentences effectively convey purpose, usage, and default behavior with no waste. Front-loaded for quick agent scanning.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness4/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given 100% schema coverage and no output schema, the description covers important aspects: purpose, usage context, and default behavior. Missing explicit return format but adequate for a simple pass/fail tool.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  Schema coverage is 100%, so baseline is 3. The description adds that defaults are Google's 'poor' boundaries, which is already in the thresholds parameter description, providing minimal extra value.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the tool performs a 'pass/fail check against performance thresholds' for CI quality gates, differentiating it from sibling tools like analyze_performance and compare_performance.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines4/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  It explicitly recommends use for 'CI quality gates,' providing clear context. It does not mention when not to use, but the usage is well-defined.

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

• crawl_siteA
  4/5.0
  Behavior3/5

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

  Discloses limits (max pages, parallel runs) and output structure, but with no annotations, it could mention more traits like potential slowness or authentication needs.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  Three concise sentences: purpose, output, constraints. No wasted words, front-loaded.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness4/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Covers purpose, output, and constraints adequately for a tool with few parameters and no output schema. Could include error handling or behavior on missing sitemap.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters3/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  Schema covers all 3 parameters (100% coverage), so description adds little beyond clarifying crawling method for url. Baseline 3 is appropriate.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  Description clearly states it discovers all pages via sitemap or crawling and runs Lighthouse, returning per-page and summary results. This distinguishes it from siblings that focus on single pages or comparisons.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines4/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  Provides context (site-wide audit) and constraints (max 20 pages, 3 parallel runs), but does not explicitly state when to use vs alternatives like analyze_performance for single pages.

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

• compare_performanceA
  4.1/5.0
  Behavior3/5

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

  No annotations exist, so the description must carry the full burden. It effectively communicates that this is a read-only comparison tool showing deltas and winners. However, it lacks details on data freshness, caching, or prerequisites (e.g., CrUX data availability), which would have raised the score.

  Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

  Conciseness5/5

  Is the description appropriately sized, front-loaded, and free of redundancy?

  Two well-structured sentences. The first sentence defines the action and scope, the second specifies the output format. Every word is necessary, and the description is front-loaded with critical information.

  Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

  Completeness3/5

  Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

  Given the moderate complexity and absence of output schema and annotations, the description covers the core functionality well but omits details like the specific metrics (LCP, FID, CLS), data source, and whether it works for any URL or only those with CrUX data. These gaps reduce completeness.

  Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

  Parameters4/5

  Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

  Schema description coverage is 100%, and the description adds value by explaining the behavior when urlB is omitted (compares urlA mobile vs desktop) and the default device. This goes beyond the schema's parameter descriptions, providing practical usage instructions.

  Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

  Purpose5/5

  Does the description clearly state what the tool does and how it differs from similar tools?

  The description clearly states the tool compares Core Web Vitals between two URLs or the same URL on different devices, with a specific output of per-metric deltas and winner indicators. It distinguishes itself from siblings like analyze_performance, which likely handles single URLs.

  Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

  Usage Guidelines4/5

  Does the description explain when to use this tool, when not to, or what alternatives exist?

  The description provides clear use cases: comparing two URLs or the same URL across devices. It explains the fallback when urlB is omitted, giving implicit guidance on when to include it. While it doesn't explicitly name alternatives, the sibling tools provide context for when not to use this tool.

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