list_allowed_directories
Returns the list of directories that this server is allowed to access. Subdirectories within these allowed directories are also accessible. Use this to understand which directories and their nested paths are available before trying to access files.
This record as markdown: /tools/filesystem/list-allowed-directories.md
What list_allowed_directories does on Filesystem
AI agents call list_allowed_directories to retrieve information from Filesystem without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why list_allowed_directories is rated Low
This tool queries and returns information about accessible directory paths. It is purely informational—it retrieves metadata about the filesystem structure the server exposes without creating, modifying, deleting, or executing anything. This is a classic Read operation with minimal risk.
From the tool's definition Tool name 'list_allowed_directories' and description 'Returns the list of directories' indicate data retrieval without modification. No side effects or state changes.
Attacks that exploit this kind of access
The rule that runs list_allowed_directories safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Filesystem, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For list_allowed_directories, this is the rule to start with:
list_allowed_directories 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 Filesystem, apply this rule, and every list_allowed_directories call is checked against it from then on.
Questions about list_allowed_directories
Returns the list of directories that this server is allowed to access. Subdirectories within these allowed directories are also accessible. Use this to understand which directories and their nested paths are available before trying to access files. 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_allowed_directories: 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_allowed_directories 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_allowed_directories 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_allowed_directories. 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_allowed_directories is provided by the Filesystem MCP server (@modelcontextprotocol/server-filesystem). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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