cancel_eventCancel a calendar event and automatically notify all attendees. Verify the correct event first, as this action cannot be undone.
Cancel an event and notify every attendee. This CANNOT be undone. Read the event with get_event first and be sure it is the right one.
| Name | Required | Description | Default |
|---|---|---|---|
| message | No | optional note to attendees | |
| event_id | Yes | id from list_events |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already include destructiveHint=true, but the description adds specific behavioral consequences: every attendee is notified and the action cannot be undone. This tells the agent exactly what destructive means in this context and encourages a verification step. No contradiction with annotations.
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, each carrying distinct information: purpose and effect, irreversibility, and a safety precondition. No wasted words and the most critical information is 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?
The tool has only one required parameter, no output schema, and annotations covering safety. The description covers the action, side effects, irreversibility, and a verification step, which is sufficient for an agent to call it correctly. Without an output schema, return-value detail is not required.
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 coverage is 100% — both event_id and message have descriptions. The description does not add parameter-level detail beyond the schema, though it reinforces that event_id should be verified via get_event. This meets the baseline for full schema coverage.
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?
The description states a specific action ('Cancel an event') and its immediate effect ('notify every attendee'). This clearly distinguishes it from siblings like update_event, get_event, and create_event, and there is no delete_event competing tool. The title reinforces but does not carry the description.
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?
It gives a concrete precondition: read the event with get_event first and verify it is the right one. This tells the agent when to use the tool and the necessary safety step. It does not explicitly contrast with update_event or state when not to use, but the instruction is clear enough for correct invocation.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.