Set or clear recurrence rules for Apple Calendar events using RRULE strings such as FREQ=WEEKLY;COUNT=5. Passing an empty string removes the recurrence.
Set an event recurrence rule (for example FREQ=WEEKLY;COUNT=5); empty string clears recurrence. Calendar validates the rule.
| Name | Required | Description | Default |
|---|---|---|---|
| uid | Yes | ||
| calendar | Yes | ||
| recurrence | Yes |
Changes observed during successful MCP inspections.
v3.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare destructiveHint=true and idempotentHint=true, so the safety profile is covered. The description adds genuine behavioral context beyond them: that the calendar validates the rule (so it can fail) and that an empty string is the clearing sentinel rather than an error.
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?
A single dense sentence whose clauses (example format, clear sentinel, validation note) each add distinct information, with the primary action front-loaded.
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?
For a setter with no output schema, the description covers the semantically tricky parts (rule format, clearing, validation). It is nearly complete; only the semantics of uid/calendar selection are absent, which the bare schema also omits.
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 0% across 3 required params, so the description must carry the load. It documents the 'recurrence' format and its empty-string edge case well, but 'uid' and 'calendar' receive no explanation at all, leaving the coverage gap half-filled.
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 precise verb+resource: 'Set an event recurrence rule', with a concrete RFC-5545 style example. The recurrence focus makes it reasonably distinguishable from siblings like apple_calendar_update_event or apple_calendar_add_alarm, though it doesn't explicitly name what it is not.
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?
'empty string clears recurrence' hints at when you would call it in the clear case, but there is no explicit guidance on when to use this tool versus apple_calendar_update_event, nor any prerequisites (e.g. event must already exist).
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.