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Change an event

events_edit
Destructive

Change an event the account organises, in place and in one call: its subject, body, location, start and end, how it shows, its privacy, reminders and video link, and its guests - addGuests invited, removeGuests taken off. Only what is named changes: the event keeps its id, every other guest's answer and its join link, a start named alone keeps its length and an end named alone keeps its start. Start and end are named as events_create names them, so naming both in the other form turns a timed event all-day or back, and are written in the person's own time zone as events_create writes them. What the account's provider lacks is refused with the reason, as on events_create, and so is a new body for an Outlook online meeting, whose join details it holds. Changing guests takes inviting allowed on the account. A whole series' start and end are its first occurrence's, and a change to a whole series holding occurrences changed apart from it is refused, naming each by when its series set it, so none of theirs is undone. Its provider sends a meeting's guests the change from the account's own address, as notify chooses. Like every write, the answer names the event's provider, its calendarId where its provider addresses it by one, and its webLink. Guests' own hours hold a change as they hold events_create: every guest's where its times change, an added guest's at its time otherwise.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
endNo
bodyNo
scopeNoFor an occurrence of a recurring series: occurrence, where omitted, acts on that occurrence alone, series on its whole series. A series named by its own seriesId is refused unless series is passed.
startNo
videoNoA Meet link on a Google account or a Teams link on a work Microsoft account, given back under joinUrl.
notifyNoWho the provider tells: every guest where omitted, externalOnly only guests outside Google Calendar, none nobody. Outlook tells every guest of a meeting it makes, changes or cancels, so there only an answer goes untold.
showAsNoHow it shows; Google shows busy or free alone.
accountYesThe connected account, by the address calendars_list names.
eventIdYesThe event's id, as events_list names it.
privacyNo
subjectNo
locationNo
providerNoThe account's provider, as calendars_list names it; needed only where two connected accounts share an address.
addGuestsNoAddresses to invite.
remindersNoMinutes before its start each reminder sounds, Outlook keeping one; empty for none.
calendarIdNoThe calendar holding the event, by the calendarId events_list names; a Google account's event outside its default calendar needs it.
guestZonesNoA guest's own time zone, only as the person names it - never inferred from an address, a language or a provider.
removeGuestsNoGuests to take off, by address.
unusualHoursAgreedNoTrue only once the person has agreed to send at the hours an answer named as unusual for a guest.

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observed

TDQS

A4.5/5.0
Behavior5/5

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

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=true, openWorldHint=true): it explains preservation behaviour (id, other guests' answers, join link kept; a lone start keeps duration, a lone end keeps the start), provider-side refusals with reasons, the Outlook online-meeting body refusal, and notification fan-out ('from the account's own address, as notify chooses'). This is exactly the mutation context a destructiveHint flag alone cannot convey.

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

Conciseness3/5

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

Front-loaded with the core action and nearly every sentence carries distinct information, but it is one very long, densely packed paragraph with idiosyncratic phrasing that makes it hard to scan. The size is justified by the complexity, yet the structure costs readability.

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

Completeness5/5

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

For a 19-parameter mutation tool with no output schema, it covers what an agent needs: patch semantics, recurring-series scope and refusals, provider limitations, notification behaviour, and the shape of the response (provider, calendarId where applicable, webLink). Remaining gaps (e.g. reminders format) are handled by schema descriptions.

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

Parameters4/5

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

Schema coverage is only 68%, and the description compensates: it clarifies that start/end are named as events_create names them and that naming both in the other form flips timed/all-day, that times are in the person's own time zone, and that addGuests/removeGuests take guests on and off. The guestZones/'own hours' sentence also explains cross-field timing behaviour. It adds real meaning where the schema is silent.

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?

States a precise verb+resource ('Change an event the account organises, in place and in one call') and then enumerates exactly which fields the update can touch (subject, body, location, start/end, showAs, privacy, reminders, video, guests). An agent can distinguish it from events_create and events_cancel from the description alone.

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?

Gives clear operating conditions: partial-patch semantics ('Only what is named changes'), the occurrence-vs-series choice and the rule that a whole series with separately-changed occurrences is refused, and the precondition that changing guests requires inviting to be allowed on the account. It does not explicitly route to sibling tools (e.g. use events_create to make a new event), so it stops short of a 5.

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

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