AI agents use create_event to create or update resources in Lark MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Lark MCP Server environment.
Creating a calendar event is a Write operation: it creates new data (calendar entry) but the action is reversible (the event can be deleted or modified). It does not execute arbitrary code, delete data irreversibly, or move money.
From the tool's definition Tool description states 'Create a calendar event on Lark' — creates new calendar entries which are reversible modifications.
Documented attack patterns abuse exactly the kind of access create_event gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Lark MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for create_event:
{
"version": "1",
"default": "deny",
"tools": {
"create_event": {
"limits": [
{
"counter": "create_event_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_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.
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Create a calendar event on Lark. It is categorised as a Write tool in the Lark MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Lark MCP Server MCP server in PolicyLayer and add a rule for create_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 Lark MCP Server. Nothing to install.
create_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 create_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 create_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.
create_event is provided by the Lark MCP Server MCP server (junyuan-qi/lark-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Lark MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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5 Lark MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.