owa-mail-mcp

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Update Calendar Event

update_event

Destructive

Modify an existing calendar event's details and notify attendees. Supports recurring event updates with apply_to for this event or entire series.

Instructions

Change an existing event and notify attendees. Only the fields you pass change.

For a RECURRING event apply_to is required, and nothing is changed until you supply it.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "item_id": "<item_id>"
    },
    "name": "update_event"
  }
}

Input Schema

Name	Required	Description	Default
`end`	No	new end time, ISO 8601.
`body`	No
`start`	No	new start time, ISO 8601.
`item_id`	Yes	item_id from get_calendar_events.
`subject`	No
`apply_to`	No	recurring events only — "this_event" changes just this one, "whole_series" every event in the series. Required when the event is recurring (get_calendar_events marks those with is_recurring), ignored for one-off events. Ask the user which they meant rather than picking.
`location`	No
`body_type`	No	"HTML" or "Text" — applies to `body`.	HTML
`send_updates`	No	send the update to attendees.

Output Schema

Name	Required	Description	Default
`result`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

First observedv0.1.0Aug 6, 2026

TDQS

A4.2/5.0

Behavior4/5

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

Annotations already flag destructiveHint and readOnlyHint, but the description adds valuable context beyond them: it notifies attendees, only applies to passed fields (not a full replace), and for recurring events nothing changes until apply_to is supplied. These are meaningful behavioral details.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is two short, purposeful sentences. The first states the action and side effect; the second clarifies the recurring-event constraint. No filler or repetition—concise and well-structured.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a tool with recurring-event complexity and attendee notifications, the description covers the essential behaviors: partial update, notification, and the apply_to requirement. An output schema exists, so return details are not necessary. It lacks error/edge-case guidance but is sufficient for most scenarios.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 67% and the schema already documents key parameters like apply_to, body_type, and send_updates in detail. The description's mention of apply_to being required repeats schema info without adding new meaning. It also does not compensate for the three undocumented parameters (body, subject, location).

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description uses a specific verb ('Change') and resource ('existing event'), and includes 'notify attendees' which distinguishes it from create/cancel/respond siblings. It also clarifies the partial-update behavior, making the tool's purpose unmistakable.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

It clearly implies use for modifying existing events ('Change an existing event') and provides context for recurring events (apply_to required). However, it does not explicitly name alternative tools or state when not to use it, so it falls short of full usage guidance.

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