AI agents use lark_send_text to create or update resources in Notify MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Notify MCP Server environment.
The tool creates and sends messages to a Lark (collaboration platform) chat, which is a reversible write operation. It does not execute arbitrary code, delete data, or move money. However, it has medium severity because unsolicited or malicious messages sent through a compromised AI agent could spam users, phish for credentials, or spread misinformation within an organization's communication channel.
From the tool's definition Tool name 'lark_send_text' and description indicating it sends text or Markdown messages to Lark/飞书 group bots ('飞书/Lark群机器人发送文本或Markdown消息'). This is a message-sending operation that modifies state in an external communication platform.
Documented attack patterns abuse exactly the kind of access lark_send_text gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Notify MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for lark_send_text:
{
"version": "1",
"default": "deny",
"tools": {
"lark_send_text": {
"limits": [
{
"counter": "lark_send_text_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}lark_send_text 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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飞书/Lark群机器人发送文本或Markdown消息. It is categorised as a Write tool in the Notify MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Notify MCP Server MCP server in PolicyLayer and add a rule for lark_send_text: 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 Notify MCP Server. Nothing to install.
lark_send_text 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 lark_send_text 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 lark_send_text. 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.
lark_send_text is provided by the Notify MCP Server MCP server (oci:ghcr.io/aahl/mcp-notify:latest). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Notify MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
21 Notify MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.