Get Calendar Event Changes

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

Annotations already declare readOnly, idempotent, and non-destructive, so the safety bar is lower; the description still adds substantive context: the calendar.read permission requirement, the meaning of sync_required, and the caveat that coalesced changes are not a complete activity history. That last point is a real behavioral caveat an agent could otherwise misuse.

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 and followed by the permission requirement and the sync caveat. Every sentence contributes, though the first sentence is compressed to the point of mild ambiguity about what a 'retained state' is.

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 an output schema present, return values need not be explained, and the description still covers the key output flag (sync_required) and the credential scope implication. It is close to complete for a three-optional-parameter read tool, missing only explicit sibling routing.

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 all three parameters are documented with formats and constraints; the description adds no syntax or defaulting detail beyond that. Baseline 3 applies since the schema carries the parameter burden.

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 ('Read bounded event changes') plus the source of truth ('from a retained state'), which is precise and tells an agent this is an incremental sync operation. It does not differentiate itself from siblings like mailbox_list_calendar_events or mailbox_get_calendar_event, so an agent must infer the distinction.

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 actionable guidance for the sync_required=true case (perform a full resync) and implicitly defines the incremental flow via since_state. However, it never states when to choose this tool over mailbox_list_calendar_events or mailbox_get_calendar_event, and no explicit prerequisites or exclusions beyond the read scope are given.

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