AI agents call slack_users_list to retrieve information from Sage MCP 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 all users in a Slack workspace. While it performs no modifications, it exposes sensitive information (user identities, potentially email addresses, profiles) across an entire workspace, making it a Read operation with medium severity due to information disclosure risk if misused by an agent to profile users or extract organizational structure.
From the tool's definition Tool name 'slack_users_list' and description 'List all users in the workspace' indicate a query operation that retrieves user data without modifying anything.
Risk signalsBulk/mass operation — affects multiple targets
Documented attack patterns abuse exactly the kind of access slack_users_list gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Sage MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for slack_users_list:
{
"version": "1",
"default": "deny",
"tools": {
"slack_users_list": {}
}
}slack_users_list is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List all users in the workspace. It is categorised as a Read tool in the Sage MCP MCP Server, which means it retrieves data without modifying state.
Register the Sage MCP server in PolicyLayer and add a rule for slack_users_list: 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 Sage MCP. Nothing to install.
slack_users_list 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 slack_users_list 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 slack_users_list. 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.
slack_users_list is provided by the Sage MCP server (sagemcp/sagemcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 359 Sage MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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359 Sage MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.