AI agents use append_sheet_data to create or update resources in Personal Knowledge MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Personal Knowledge MCP Server environment.
This tool appends new rows to an existing Feishu (Lark) spreadsheet. It creates/adds data without deleting or overwriting existing content, making it a Write operation. Misuse could pollute a shared knowledge base spreadsheet with unwanted data, but it is reversible.
From the tool's definition 追加数据到飞书电子表格（在已有数据后追加新行）— 'append data to Feishu spreadsheet (append new rows after existing data)'
Documented attack patterns abuse exactly the kind of access append_sheet_data gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Personal Knowledge MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for append_sheet_data:
{
"version": "1",
"default": "deny",
"tools": {
"append_sheet_data": {
"limits": [
{
"counter": "append_sheet_data_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}append_sheet_data 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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追加数据到飞书电子表格（在已有数据后追加新行）. It is categorised as a Write tool in the Personal Knowledge MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Personal Knowledge MCP Server MCP server in PolicyLayer and add a rule for append_sheet_data: 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 Personal Knowledge MCP Server. Nothing to install.
append_sheet_data 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 append_sheet_data 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 append_sheet_data. 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.
append_sheet_data is provided by the Personal Knowledge MCP Server MCP server (kyodule/personal-knowledge-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Personal Knowledge 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.
29 Personal Knowledge MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.