Modify specific fields of an existing Google Calendar event by passing only the values you want changed, such as time, title, location, or attendees.
Partial update of an existing event. Only pass the fields you want to change. Uses PATCH semantics.
| Name | Required | Description | Default |
|---|---|---|---|
| end | No | ||
| start | No | ||
| summary | No | ||
| event_id | Yes | ||
| location | No | ||
| timezone | No | ||
| attendees | No | ||
| calendar_id | No | primary | |
| description | No | ||
| send_updates | No | none |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full burden, and it does add one genuinely useful trait: PATCH semantics, meaning omitted fields are left unchanged. However, it says nothing about side effects such as attendee notifications via send_updates, authorization requirements, or whether the update is reversible, which matters for a mutation tool.
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 purpose and free of padding. 'Uses PATCH semantics' slightly restates the preceding partial-update sentence, but it is a useful reinforcement rather than filler.
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 10-parameter mutation tool with no annotations, no output schema, and zero schema description coverage, the description is far too thin. An agent cannot tell what a successful response looks like, what happens to attendees, or how the enum and defaulted parameters behave.
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 10 parameters, so the description must compensate and largely does not. It never explains send_updates (the one enum, controlling who is notified), calendar_id's 'primary' default, the timezone or attendee semantics, or the expected format for start/end. 'PATCH semantics' only partially covers the update contract.
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 ('Partial update of an existing event'), which distinguishes it from create_event and delete_event by name. It is clear about what it operates on, though it does not explicitly contrast itself with the sibling set beyond the verb.
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?
'Only pass the fields you want to change' gives real guidance on how to invoke it, but there is no statement of when to use update_event versus create_event or delete_event, nor any prerequisites such as required permissions or ownership of the event.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.