AI agents call list-shares to retrieve information from Nextcloud without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and displays existing share information without creating, modifying, or removing any data. It is purely informational and has no side effects on the system state. The low severity reflects minimal risk even if an AI agent calls this tool, as it only exposes information about shares without enabling unauthorized access or data changes.
From the tool's definition Tool name 'list-shares' and description 'List existing shares' indicate a query/retrieval operation with no modification or deletion of data.
Attacks that exploit this kind of access
List existing shares. It is categorised as a Read tool in the Nextcloud MCP Server, which means it retrieves data without modifying state.
Register the Nextcloud MCP server in PolicyLayer and add a rule for list-shares: 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 Nextcloud. Nothing to install.
list-shares 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-shares 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-shares. 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-shares is provided by the Nextcloud MCP server (nextcloud-mcp-server). 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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