Measure page speed

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

The description goes well beyond the readOnlyHint annotation by disclosing rate limiting, repeated polling, min-max spread, job ID behavior, timing, and honest degradation if time runs out. This rich operational detail is exactly the kind of context that helps an agent behave correctly.

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?

Although the description is long, every sentence conveys a decision-relevant fact: noise, rate limits, timing, job handling, and immediate-answer conditions. The main uncertainty point is front-loaded, and the structure builds logically from behavior to usage constraints.

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?

Given no output schema, the description still mentions it returns a report and JSON figures. It covers latency, polling, job IDs, parameter behavior, and edge cases like time running out. An agent has enough context to call the tool and interpret results safely.

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%, so the baseline is 3, but the description adds meaningful behavioral semantics for the parameters: runs=1 is noisy, runs=5 takes ~150 seconds, and strategy defaults to mobile because Google ranks on it. This goes beyond what the schema alone states.

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 identifies the tool as measuring a page with Google PageSpeed Insights and reporting the median of distinct analyses with min-max spread. This specific verb-resource pair distinguishes it from the sibling tools by emphasizing the repeated-analysis uncertainty behavior.

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?

It explicitly warns against using runs=1 and quoting the noisy score, notes that `check_status` should be used to collect jobs, and explains when immediate answers are possible. This gives clear when-to-use and when-not-to-use guidance beyond a generic description.

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