List files in a directory.
AI agents call ls to retrieve information from MCP File System Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The ls tool performs directory listing, which is a read-only operation with no side effects. It retrieves information about files and directories but does not create, modify, delete, or execute anything. This is a fundamental safe operation with minimal risk if misused by an AI agent.
From the tool's definition Tool name 'ls' and description 'List files in a directory' indicate a query operation that retrieves directory contents without modifying state.
Attacks that exploit this kind of access
List files in a directory. It is categorised as a Read tool in the MCP File System Server MCP Server, which means it retrieves data without modifying state.
Register the MCP File System Server MCP server in PolicyLayer and add a rule for ls: 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 MCP File System Server. Nothing to install.
ls 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 ls 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 ls. 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.
ls is provided by the MCP File System Server MCP server (kvas-it/mcp-server-fs). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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