This record as markdown: /tools/io-github-portel-dev-ncp/update-event.md
What update_event does on Ncp
AI agents use update_event to create or update resources in Ncp, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Ncp environment.
Why update_event is rated Medium
This tool creates or modifies data reversibly by updating calendar events. It does not delete data (would be Destructive), execute arbitrary code (would be Execute), or move money (would be Financial). The impact is limited to calendar data modification, which is a write operation.
From the tool's definition Tool name 'update_event' combined with description 'Update existing calendar event' indicates modification of existing data (calendar events).
Attacks that exploit this kind of access
The rule that runs update_event safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Ncp, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For update_event, this is the rule to start with:
update_event stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Ncp, apply this rule, and every update_event call is checked against it from then on.
Questions about update_event
Update existing calendar event. It is categorised as a Write tool in the Ncp MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Ncp MCP server in PolicyLayer and add a rule for update_event: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Ncp. Nothing to install.
update_event is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the update_event rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for update_event. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
update_event is provided by the Ncp MCP server (@portel/ncp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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