List contents of a directory. Returns files and subdirectories with metadata. Supports pagination via limit and offset.
AI agents call filesystem_listdir to retrieve information from Truenas without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool retrieves and queries directory contents with metadata but performs no modifications, deletions, executions, or financial operations. It is a straightforward directory listing operation analogous to 'ls' or 'readdir', making it a Read category risk with low severity since directory listing is a basic, non-destructive information retrieval operation.
From the tool's definition Tool name is 'filesystem_listdir' and description explicitly states 'List contents of a directory. Returns files and subdirectories with metadata.' This is a pure read operation with no side effects.
Documented attack patterns abuse exactly the kind of access filesystem_listdir gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Truenas, and nothing reaches the server without passing your rules. This is the rule we recommend for filesystem_listdir:
{
"version": "1",
"default": "deny",
"tools": {
"filesystem_listdir": {}
}
}filesystem_listdir is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List contents of a directory. Returns files and subdirectories with metadata. Supports pagination via limit and offset. It is categorised as a Read tool in the Truenas MCP Server, which means it retrieves data without modifying state.
Register the Truenas MCP server in PolicyLayer and add a rule for filesystem_listdir: 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 Truenas. Nothing to install.
filesystem_listdir is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the filesystem_listdir 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 filesystem_listdir. 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.
filesystem_listdir is provided by the Truenas MCP server (spranab/truenas-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Truenas, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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279 Truenas tools catalogued and risk-classified — across an index of 43,000+ MCP servers.