get_vitals_metrics

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

Without annotations, the description fully discloses that the tool is a placeholder and returns placeholder data, which is a critical behavioral trait. It does not explicitly state it is read-only, but the 'get' name and return indication imply that.

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 very concise, using two sentences for the intro and simple bullet-like Args/Returns. It front-loads the placeholder nature, and every sentence adds value. No extraneous text.

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 the tool is a placeholder, the description adequately covers its basic purpose, limitations, and parameters. The output schema is assumed to cover return format. Missing details on error handling or prerequisites beyond the API note, but sufficient for a placeholder.

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?

Both parameters are explained: 'package_name' as 'App package name' and 'metric_type' as 'Type of metric to retrieve' with examples like 'crashRate, anrRate'. Given 0% schema coverage, this adds essential meaning beyond names and types.

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 states the tool retrieves specific Android Vitals metrics, but immediately notes it is a placeholder, which reduces its utility. It does not explicitly distinguish from sibling 'get_vitals_overview', though 'specific' versus 'overview' implies differentiation.

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?

The description mentions it 'requires Play Developer Reporting API' and that full implementation needs a separate API, providing some context on prerequisites. However, it does not specify when to avoid using it, nor does it mention alternatives like 'get_vitals_overview'.

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