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

Beyond the readOnlyHint/idempotentHint annotations, the description discloses important behaviors: recurring events are expanded to occurrences, results are sorted by start, and timezone handling defaults to the profile's or machine's zone unless overridden. It also states that returned ids are compatible with event_export and event_to_time_entry. These details add meaningful context beyond the structured 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 concise and well-structured: three sentences each earn their place. The core function and scope are front-loaded, followed by timezone behavior and integration guidance. There is no redundant or vague wording.

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 the essential behavioral context and integration points, and annotations handle the safety profile. It does not describe the returned event fields or pagination, but for a read-only list tool with fully described parameters, it is largely sufficient. The lack of an output schema could be compensated by a note on the return structure, but it is not a critical omission.

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 coverage is 100%, so the baseline is 3. The description adds nuance to the 'zone' parameter by specifying the fallback order ('profile's, else this machine's'), which is not in the schema. It also implicitly explains how from/to define the window. This extra clarity justifies a slight increase over the baseline.

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 a specific verb and resource: it lists events between two dates, with recurrence expanded and sorted by start. It does not explicitly contrast with sibling events_search, but the phrase 'Every event' implies broad, unfiltered coverage, which helps distinguish it. Overall the purpose is unambiguous.

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 clear context for when to use the tool: when all events in a date range are needed. It also notes that each id works for event_export or event_to_time_entry, providing guidance on related follow-up tools. It does not explicitly name alternatives or exclusion cases, but the primary use case is evident.

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