Chrome UX Report: andamento

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

Annotations already declare readOnlyHint and openWorldHint, so safety is covered. Description adds that data is real CrUX, 75th percentile, weekly rows up to 40 weeks, which is useful output-shape context, but it omits auth, rate limits, or data freshness caveats.

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, no filler, front-loaded with scope and followed by use case. Every sentence earns its place.

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 4-param, no-output-schema tool, the description gives the metric set and weekly granularity, but it does not clarify how url and origin interact, the default weeks value (25), or any output column names. It is adequate but missing details an agent may need.

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 75% (url, origin, formFactor have descriptions; weeks does not). The description mentions 'fino a 40 settimane' which aligns with the weeks parameter maximum, but adds no syntax or default/format detail beyond the schema. Baseline 3 is appropriate.

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?

States a specific resource (real Core Web Vitals trend at 75th percentile), granularity (one row per week, up to 40 weeks), and a concrete use case. It distinguishes itself from crux_query via the historical/trend scope, though it does not explicitly name the sibling.

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?

Provides a clear context: useful for checking whether an intervention improved or worsened performance. However, it does not state when to use this instead of crux_query or other performance tools, nor any exclusions.

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