crux_query

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

No annotations are present, so the description carries the burden of explaining behavior. It implies a non-destructive read operation, but it does not disclose whether authentication is needed, whether at least one of url/origin is required, how much data is returned, or what performance metrics are actually included. This is minimal transparency beyond the bare action.

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?

The description is a single concise sentence with no filler and the core action is front-loaded. However, it is short mainly because it omits important usage and behavioral details, so it is concise but not richly informative.

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?

With four parameters, no required flags, no output schema, and no annotations, the description leaves the agent unsure about how to form a valid call, what the response looks like, and what constraints apply. It communicates the basic purpose but is not complete enough for correct invocation.

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 0%, and the description adds no meaning to the four parameters: url, origin, metrics, and formFactor. It does not explain what each parameter controls, whether url and origin are mutually exclusive, or what metric strings are valid beyond the enum values already visible in the schema. The description entirely fails to compensate for the missing schema descriptions.

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 uses a specific verb, 'Queries', and identifies the resource, 'Chrome UX Report data', along with the purpose, 'real-world performance metrics'. This clearly states what the tool does, but it does not differentiate it from sibling tools like crux_history, cwv_report, or psi_analyze, which could overlap in purpose.

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?

No guidance is provided about when to use crux_query versus alternatives. There is no mention of whether to pass a url or origin, whether both are needed, what kind of report this returns, or when a sibling like crux_history would be more appropriate. The agent receives no routing help.

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