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

Annotations already declare readOnlyHint=true and idempotentHint=true, so the safety profile is covered. The description adds useful context: data source (daily aggregates), retention (12 months), and timezone handling. However, it does not disclose output format, behavior with empty results, or what 'previous period' means, leaving some ambiguity.

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 ('Event counts over a range of calendar days') and then add relevant detail. No fluff or redundancy; every phrase contributes value.

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 description covers key aspects: what is counted, scope, data source, and timezone. However, terms like 'per level' and 'previous period' are ambiguous—'level' could refer to severity or event type, and 'previous period' is not defined (previous day, week, or same period last year). Given no output schema, these gaps could confuse an agent, but overall it is adequate for a reporting 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%, with each parameter clearly explained (e.g., 'to' as 'Last calendar date (YYYY-MM-DD, org-local); with from.'). The description does not add parameter-specific details beyond the schema, but it provides general context ('Dates only') that aligns with the schema. Baseline 3 is appropriate given high 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: 'Event counts over a range of calendar days' with explicit dimensions (per day, per level, in total, against previous period) and scope (whole organization or one event name). This distinguishes it from siblings like get_user_timeline (per-user activity) or get_event (single event details) without needing to open schemas.

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 implies usage for aggregated event counts over time but does not explicitly state when to use this tool versus alternatives or when not to use it. There are no exclusions mentioned, and no reference to sibling tools. The context ('Dates only, org time zone') is a constraint, not usage guidance.

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