List users in the Slack workspace
AI agents call slack_list_users to retrieve information from Slack MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns user data from the Slack workspace without creating, modifying, deleting, or executing any operations. It is a read-only information retrieval operation with minimal security impact, as it only exposes workspace user directory information.
From the tool's definition Tool name 'slack_list_users' and description 'List users in the Slack workspace' indicate retrieval of user information with no modification, deletion, or side effects.
Attacks that exploit this kind of access
List users in the Slack workspace. It is categorised as a Read tool in the Slack MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Slack MCP Server MCP server in PolicyLayer and add a rule for slack_list_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 Slack MCP Server. Nothing to install.
slack_list_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 slack_list_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 slack_list_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.
slack_list_users is provided by the Slack MCP Server MCP server (sdancy10/slack-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
slack_list_users is one line of Slack MCP Server's registry record.
The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.
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