TimeTree MCP Server

update_event_occurrence

Destructive

Change one occurrence of a recurring event or that occurrence and all later ones while keeping earlier occurrences unchanged; use update_event to edit the full series.

Instructions

Change one occurrence of a recurring event ("only this week"), or that occurrence and all later ones (scope "this_and_following", e.g. "from next month on"), keeping earlier occurrences as they are. Use update_event to change the whole series. Get the series uuid and occurrence_start_at from get_events with start_before set. Only provide the fields to change; start_at moves the occurrence and keeps its length unless end_at is given. scope "this" creates a separate event linked to the series (parent_id); "this_and_following" ends the series before the occurrence and starts a new series with a new uuid, or changes the whole series when it is the first occurrence.

Input Schema

TableJSON Schema

Name	Required	Description
`url`	No	New related URL
`note`	No	New note
`scope`	No	"this" (default) changes only this occurrence; "this_and_following" also changes every later one
`title`	No	New title
`alerts`	No	Replace notification offsets in minutes
`end_at`	No	New end time as Unix timestamp in milliseconds
`label_id`	No	Color label ID (1-10): 1=Emerald green, 2=Modern cyan, 3=Deep sky blue, 4=Pastel brown, 5=Midnight black, 6=Apple red, 7=French rose, 8=Coral pink, 9=Bright orange, 10=Soft violet
`location`	No	New location
`start_at`	No	New start time as Unix timestamp in milliseconds
`attendees`	No	Replace attendee user IDs
`checklist`	No	Replace checklist items
`event_uuid`	Yes	The recurring series uuid (the uuid get_events returns for every occurrence)
`calendar_id`	Yes	The calendar ID from list_calendars (numeric string; numbers are also accepted)
`recurrences`	No	Only with scope "this_and_following": a new RRULE for the new series, e.g. ["RRULE:FREQ=WEEKLY;INTERVAL=2"]. Required when start_at or start_timezone moves the occurrences to another day and the rule uses BYDAY, BYMONTHDAY, or BYMONTH. Without COUNT or UNTIL, the remaining count or end carries over, and so do deleted later occurrences unless an EXDATE is given.
`end_timezone`	No	New end timezone
`start_timezone`	No	New start timezone (e.g., "Asia/Seoul")
`occurrence_start_at`	Yes	Start of the occurrence, exactly as get_events returned it (ISO 8601), or Unix ms
`virtual_user_attendees`	No	Replace virtual member attendees

Output Schema

TableJSON Schema

Name	Required	Description
`event`	Yes
`scope`	Yes
`result`	Yes
`message`	No
`success`	Yes
`series_uuid`	Yes	The series the occurrence belonged to
`occurrence_start_at`	Yes	ISO 8601 date-time (UTC)

Schema Changelog

Changes observed during successful MCP inspections.

Addedv0.7.0Oct 22, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Annotations already declare destructiveHint=true and non-idempotent, and the description earns more credit by disclosing the actual side effects: scope "this" spawns a separate parent-linked event, while "this_and_following" truncates the series and starts a new one with a new uuid (or edits the whole series when the occurrence is first). That is exactly the consequence information an agent needs before mutating a recurrence.

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

Conciseness4/5

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

Front-loaded with the core scope distinction and the sibling alternative before the mechanics. It is a dense, somewhat run-on paragraph, but at 18 parameters the length is largely justified and every clause carries operational meaning.

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 destructive, non-idempotent recurrence mutation with an output schema and full annotation coverage, the description supplies everything missing: prerequisites, scope semantics, downstream structural effects, and partial-update conventions.

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 100%, so the schema already defines all 18 parameters. The description still adds real semantics beyond it, notably that start_at relocates the occurrence and preserves its duration unless end_at is supplied, and that recurrences only applies with "this_and_following".

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 specific verb and resource plus the exact scope of the change: one occurrence ("only this week") versus that occurrence and all later ones. It explicitly names update_event as the whole-series alternative, so the agent can distinguish it from siblings without opening either schema.

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

Usage Guidelines5/5

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

Gives explicit routing rules: use update_event for the whole series, and obtain the series uuid plus occurrence_start_at from get_events with start_before set. Also instructs to supply only the fields being changed, which prevents accidental overwrites.

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