filesystem_listdir
List contents of a directory. Returns files and subdirectories with metadata. Supports pagination via limit and offset.
This record as markdown: /tools/spranab-truenas-mcp/filesystem-listdir.md
What filesystem_listdir does on Truenas
AI agents call filesystem_listdir to retrieve information from Truenas without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why filesystem_listdir is rated Low
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.
Attacks that exploit this kind of access
The rule that runs filesystem_listdir safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Truenas, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For filesystem_listdir, this is the rule to start with:
filesystem_listdir is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Truenas, apply this rule, and every filesystem_listdir call is checked against it from then on.
Questions about filesystem_listdir
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.
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