User Session Count

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds that it returns per-day session counts across a time range, which aligns with the annotations. It does not disclose additional behaviors like rate limits or handling of missing data, but given the annotations, the description provides sufficient extra context.

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 extremely concise, consisting of two sentences with no unnecessary words. It is front-loaded with the core purpose and immediately adds a relevant use case.

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's simplicity (per-day count for a user), the description is mostly complete. It explains the output (per-day session count) and a use case. However, it does not specify the exact return structure (e.g., array of {date, count}), which could be inferred. No output schema exists, so a bit more detail might help, but it's still adequate.

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 71%, so the schema already documents most parameters. The description does not add parameter-specific details beyond the schema. The reference to 'time range' implies the date parameters, but this is already covered in the schema. Baseline 3 is appropriate.

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 verb 'Get' and the resource 'per-day session count for a single user across the requested time range'. It also provides a specific use case (plotting user engagement intensity with calendar heatmap or sparkline), which differentiates it from sibling tools like rybbit_get_session or rybbit_list_sessions.

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 context on when to use the tool (for per-day user engagement intensity), but does not explicitly state when not to use it or mention alternatives. However, the description is sufficient to infer its purpose relative to siblings.

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