play_vitals

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

With no annotations provided, the description carries the full burden. It states 'Read-only,' which is a key behavioral trait, and mentions that it reports data freshness, giving extra context. It does not detail rate limits, pagination, or error handling, but the read-only nature and freshness reporting are valuable disclosures that go beyond minimal.

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 three sentences, each serving a purpose: stating the core function, highlighting a unique feature (freshness), and providing an exclusion. It is concise and well-organized, though the freshness statement could be integrated more tightly, but it is still efficient.

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?

The tool is complex (7 parameters, output schema), but the description covers purpose, key behavioral aspects (read-only, freshness), and a sibling alternative. It does not explicitly state when to use it (beyond data type), but given the schema and output schema exist, the essential information is present. The lack of explicit 'use when' guidance is a minor gap, making it a 4 rather than a 5.

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 every parameter is already documented. The description adds minimal parameter-specific value—it mentions 'daily or hourly' (aggregationPeriod) and 'optional breakdowns' (dimensions) but does not elaborate beyond what the schema already states. Given the full schema coverage, the baseline of 3 is appropriate; the description supplements slightly but does not carry much extra semantic load.

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 reads Android vitals (crash rate, ANR rate, error counts, startup metrics) from the Play Developer Reporting API, with temporal granularity and breakdown options. It explicitly names the data domain and scope, distinguishing it from sibling tools like play_store_stats. The verb 'read' and resource 'Android vitals' are specific.

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 explicitly says it carries no acquisition or conversion data and directs users to play_store_stats for that, providing a clear exclusion and alternative. However, it does not offer broader 'when to use' guidance beyond the data-type distinction, and it does not mention other potential alternatives for metrics not covered, though that is sufficient.

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