AI agents call search_users to retrieve information from Teams without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries an organizational directory and retrieves basic user profile data without any side effects. It performs a passive lookup operation typical of Read category tools. The blast radius of misuse is limited to potential exposure of non-sensitive user directory information that is typically already semi-public in most organizations.
From the tool's definition Tool description states it "Search[es] for users in the organization by name or email address. Returns matching users with their basic profile information." The verb "search" combined with "returns" indicates data retrieval with no modification or deletion.
Attacks that exploit this kind of access
Search for users in the organization by name or email address. Returns matching users with their basic profile information. It is categorised as a Read tool in the Teams MCP Server, which means it retrieves data without modifying state.
Register the Teams MCP server in PolicyLayer and add a rule for search_users: 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 Teams. Nothing to install.
search_users 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 search_users 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 search_users. 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.
search_users is provided by the Teams MCP server (@floriscornel/teams-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.