run_performance_test

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

With no annotations, the description carries the full burden. It usefully discloses the runtime dependency on chrome-devtools-mcp, but says nothing about whether the test is non-destructive, how long multi-run averaging takes, or any rate/资源 constraints — meaningful gaps for a tool that launches a browser and traces a live page.

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?

Front-loaded with a clear purpose sentence, then a scannable bullet list of measured metrics, then the usage cue and prerequisite. The list is long but each item defines real output scope; slightly bulky but no filler sentences.

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?

No output schema exists, and the description partially compensates by enumerating the metric categories returned. Combined with the stated dependency, an agent has enough to call it correctly, though return format (raw JSON vs. report), runtime expectations, and error behavior remain unstated.

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 schema already documents url, runs, and throttle (including the throttle enum). The description adds no detail on parameters — no guidance on choosing runs for stable averages or when 3g/4g throttling is appropriate — so the baseline 3 applies.

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 gives a specific verb (perform performance testing) and resource (web application) and enumerates the exact metric families it produces (Core Web Vitals, load timing, resource sizes, third-party impact). That detail implicitly separates it from siblings like run_visual_test or run_seo_test, though no sibling is named explicitly.

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?

"Use this tool when you need to evaluate a website's loading performance and identify bottlenecks" states the selection condition clearly, and the final sentence adds a concrete prerequisite (chrome-devtools-mcp must be running). It does not discuss when to prefer run_full_test over this, or note exclusions, so it stops short of a 5.

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