List files/directories. Can optionally include stats and list recursively.
AI agents call list_files to retrieve information from Filesystem without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves filesystem metadata (file/directory names, optionally with stats) without creating, modifying, or deleting data. It is a straightforward query operation with minimal blast radius if misused by an AI agent—worst case being information disclosure about the filesystem structure.
From the tool's definition Tool description states 'List files/directories' with optional stats and recursive listing. The verb 'list' and the read-only nature of directory enumeration clearly indicate data retrieval with no modification or side effects.
Documented attack patterns abuse exactly the kind of access list_files gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Filesystem, and nothing reaches the server without passing your rules. This is the rule we recommend for list_files:
{
"version": "1",
"default": "deny",
"tools": {
"list_files": {}
}
}list_files is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List files/directories. Can optionally include stats and list recursively. It is categorised as a Read tool in the Filesystem MCP Server, which means it retrieves data without modifying state.
Register the Filesystem MCP server in PolicyLayer and add a rule for list_files: 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 Filesystem. Nothing to install.
list_files 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 list_files 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 list_files. 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.
list_files is provided by the Filesystem MCP server (sylphxai/filesystem-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Filesystem, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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13 Filesystem tools catalogued and risk-classified — across an index of 43,000+ MCP servers.