session_stats

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

With no annotations present, the description carries the full behavioral burden. It discloses the session definition (detectSessions, 30-min gap), the read-like nature ('1-2 reads'), and that computation is local. It does not discuss auth or edge cases, but it provides meaningful behavioral context beyond a generic summary.

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?

Two concise sentences front-load the core purpose and metrics, then add quota/cost context. Every phrase earns its place, with no filler or repetition.

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?

Despite having no output schema or annotations, the description is reasonably complete: it states the data source, session definition, returned metrics, and quota. Parameter details are fully covered by the schema, and the remaining ambiguity about the exact output shape is minor for a stats-report tool.

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 both parameters with defaults, constraints, and descriptions. The tool description does not add parameter-specific meaning beyond the schema, so the baseline score of 3 applies.

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 resource and computation: session-size distribution derived from recently-played via detectSessions with a 30-minute gap, and it enumerates the exact metrics returned. It does not explicitly name a sibling tool, but the specific source and metric list distinguish it from generic listening reports.

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 intended usage is implied: use this tool when you want session-size statistics based on recently-played history. However, it provides no explicit when-to-use or when-not-to-use guidance, and the sibling list contains many similar report/analytics tools, so an agent must infer the boundaries.

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