play_compare_versions

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

The description discloses that it 'Automatically calculates delta and percentage improvement', which is useful behavioral context beyond the schema. However, with no annotations provided, the description carries the full burden for behavioral disclosure. It doesn't mention whether this is a read-only operation, whether it requires special permissions, or what happens if versions are invalid. The delta/percentage calculation is a positive addition, but more behavioral context would be expected for a tool with zero annotations.

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 compact and front-loaded with the '[Version Comparison]' category tag, followed by a clear one-sentence purpose and a useful note about automatic delta calculation. It earns its place without being verbose. Minor improvement would be adding explicit usage guidance, but the current structure is 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?

For a comparison tool with 6 parameters and no output schema, the description covers the core purpose and the automatic calculation behavior. However, it doesn't describe the output format (what the delta/percentage looks like), which is important since there's no output schema. It also doesn't mention edge cases like missing data for a version. The description is adequate but leaves some gaps for an agent to discover at runtime.

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 the schema already documents all 6 parameters. The description adds context about the two key parameters (baseline_version and target_version) by framing them as 'before and after' versions, which helps an agent understand their relationship. However, it doesn't add detail about metric_type options or days aggregation beyond what the schema already provides. Baseline 3 is appropriate given full schema coverage.

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's purpose: comparing metrics between two app versions, with a concrete example (Baseline Profile / ANR fixes). It uses a specific verb ('Compare') and resource ('metrics between two app versions'), and the '[Version Comparison]' prefix helps distinguish it from sibling tools like play_get_metric_trends or play_get_top_anr_summary.

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 gives a clear context for when to use this tool (comparing before/after a change like Baseline Profile or ANR fixes) and implies it's for version-to-version comparison. It doesn't explicitly state when NOT to use it or name alternative tools, but the context is strong enough for an agent to select it appropriately among siblings.

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