Event User Leaderboard

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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds useful behavioral detail about the grouping key (identified_user_id + traits.username), but says nothing about scan limits (maxScan) or how anonymous users are handled.

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?

Three short sentences, with purpose and grouping front-loaded. The closing Czech example question is slightly unusual but functions as a compact use-case anchor rather than filler.

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?

An output schema exists, so return-format explanation is unnecessary, and parameter coverage is complete. Given that, the description is adequate, though it could mention defaults (topN=25, identifiedOnly=true) that affect the result.

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 all 11 parameters are already documented in the schema. The description only supplies example event names, adding little beyond the schema's own eventName description; 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?

States a specific verb and resource ('Returns the top users for a given event') with concrete examples of the ranking (who sent the most pm_sent, who clicked the most ad_click). The grouping detail (identified_user_id + traits.username) helps separate it from aggregate-style siblings, but no sibling is named explicitly.

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?

Provides example questions the tool answers ('kdo dnes poslal nejvíc vzkazů'), which implies usage, but offers no explicit when-to-use vs when-not guidance and does not point to alternatives like rybbit_get_event_aggregate or rybbit_get_user_event_breakdown.

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