List files + subdirectories. Hides denied entries (e.g. .ssh, .config).
AI agents call list_directory to retrieve information from Nexus Core without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries filesystem structure without side effects. It is a straightforward read operation. The modest blast radius (information disclosure limited by access controls and filtering) justifies 'low' severity. Confidence is high because the name and description are explicit and unambiguous.
From the tool's definition Tool name 'list_directory' and description 'List files + subdirectories' indicate retrieval of directory contents with no modification or deletion. The filtering of sensitive directories (.ssh, .config) shows defensive design that further reduces risk.
Attacks that exploit this kind of access
List files + subdirectories. Hides denied entries (e.g. .ssh, .config). It is categorised as a Read tool in the Nexus Core MCP Server, which means it retrieves data without modifying state.
Register the Nexus Core MCP server in PolicyLayer and add a rule for list_directory: 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 Nexus Core. Nothing to install.
list_directory 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_directory 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_directory. 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_directory is provided by the Nexus Core MCP server (noumenon-ai/nexus-core). 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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