AI agents use hfss_close_project to create or update resources in HFSS MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your HFSS MCP Server environment.
Closing a project is a state-modifying action that affects the current workspace, but it does not permanently delete data or trigger irreversible destruction. The session remains active, meaning the project file is not removed from disk. This fits the Write category (modifies data/state reversibly).
From the tool's definition Tool description states 'Close current project (session stays active)' — this modifies the state of the active project by closing it, which is a reversible operation (the project can be reopened).
Documented attack patterns abuse exactly the kind of access hfss_close_project gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and HFSS MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for hfss_close_project:
{
"version": "1",
"default": "deny",
"tools": {
"hfss_close_project": {
"limits": [
{
"counter": "hfss_close_project_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}hfss_close_project 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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Close current project (session stays active). It is categorised as a Write tool in the HFSS MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the HFSS MCP Server MCP server in PolicyLayer and add a rule for hfss_close_project: 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 HFSS MCP Server. Nothing to install.
hfss_close_project 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 hfss_close_project 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 hfss_close_project. 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.
hfss_close_project is provided by the HFSS MCP Server MCP server (leonardwy/hfss_mcpserver). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from HFSS 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.
28 HFSS MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.