AI agents call fs_list to retrieve information from Emcp without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
fs_list almost certainly retrieves directory contents without modifying state. Listing files is a read operation with minimal risk unless it exposes highly sensitive paths, but the default assumption for a 'list' tool is safe enumeration. Low severity because the tool cannot execute, delete, or modify data—it only discovers what exists.
From the tool's definition Tool name 'fs_list' indicates listing filesystem contents; sibling tools like 'fs_read', 'fs_mkdir', 'fs_rm', 'fs_write' confirm this is a read-only filesystem operation family.
Attacks that exploit this kind of access
fs_list. It is categorised as a Read tool in the Emcp MCP Server, which means it retrieves data without modifying state.
Register the E MCP server in PolicyLayer and add a rule for fs_list: 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 Emcp. Nothing to install.
fs_list 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 fs_list 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 fs_list. 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.
fs_list is provided by the E MCP server (slezica/emcp). 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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