AI agents call sp_list_drives to retrieve information from M365 without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and enumerates document libraries within a SharePoint site. It performs a read-only query operation that returns information about available drives/libraries without creating, modifying, deleting, or executing any actions. The blast radius is minimal—it only exposes the names and metadata of existing document libraries, which is informational rather than operational.
From the tool's definition Tool name 'sp_list_drives' and description 'List document libraries (drives) for a specific SharePoint site' indicate a retrieval operation with no modification or deletion capability.
Attacks that exploit this kind of access
List document libraries (drives) for a specific SharePoint site. REQUIRES site_id from sp_list_sites. Use this to browse a site. It is categorised as a Read tool in the M365 MCP Server, which means it retrieves data without modifying state.
Register the M365 MCP server in PolicyLayer and add a rule for sp_list_drives: 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 M365. Nothing to install.
sp_list_drives 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 sp_list_drives 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 sp_list_drives. 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.
sp_list_drives is provided by the M365 MCP server (swamirama/m365-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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