Get Calendar Event Changes

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

Annotations already declare readOnly, idempotent, non-destructive and openWorld, so the safety profile is covered. The description adds genuinely new context beyond that: the calendar.read scope requirement, the sync_required full-resync branch, and the caveat that coalesced changes are not a complete activity history.

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, front-loaded with the core action, then the permission prerequisite, then the sync_required fallback. No filler and every clause carries information an agent needs.

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?

With a 3-param all-optional schema, full schema coverage, an output schema and rich annotations, the description fills the remaining gaps: auth scope, the full-resync escape hatch, and the completeness caveat on results. Only the explicit relationship to sibling calendar tools is missing.

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 limit, mailbox_id and since_state are already fully documented, setting the baseline at 3. The description's 'bounded' and 'retained state' phrasing loosely frames since_state/limit but adds no syntax, format or default detail beyond the schema.

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 uses a specific verb and resource ('Read bounded event changes from a retained state') and adds a distinguishing qualifier about coalesced changes. It separates itself from list/get event siblings by implying an incremental delta feed, though it never names those siblings 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?

It gives a clear conditional directive for a return-value branch ('When sync_required is true, perform a full event resync'), which is real usage guidance. However, it never states when to choose this tool over mailbox_list_calendar_events or mailbox_get_calendar_event, leaving the delta-vs-list decision to inference.

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