AI agents use hwp_fill_cells to create or update resources in HWP MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your HWP MCP Server environment.
Based on naming convention and context from sibling tools, 'hwp_fill_cells' appears to modify document content by filling cells with data. This is a reversible write operation (cells can be edited or cleared later). It does not delete data (would be Destructive) or execute arbitrary code (would be Execute).
From the tool's definition Tool name 'hwp_fill_cells' suggests modifying cell data in HWP documents. Sibling tools include 'hwp_fill_table_with_data' and 'hwp_fill_column_numbers' which are clearly write operations. However, the description is empty, reducing confidence.
Documented attack patterns abuse exactly the kind of access hwp_fill_cells gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and HWP MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for hwp_fill_cells:
{
"version": "1",
"default": "deny",
"tools": {
"hwp_fill_cells": {
"limits": [
{
"counter": "hwp_fill_cells_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}hwp_fill_cells 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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hwp_fill_cells. It is categorised as a Write tool in the HWP MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the HWP MCP Server MCP server in PolicyLayer and add a rule for hwp_fill_cells: 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 HWP MCP Server. Nothing to install.
hwp_fill_cells 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 hwp_fill_cells 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 hwp_fill_cells. 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.
hwp_fill_cells is provided by the HWP MCP Server MCP server (jkf87/hwp-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from HWP 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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30 HWP MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.