List all users in the Slack workspace
AI agents call 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 retrieves user information without modifying, executing code, deleting data, or moving money. It has no side effects and simply lists existing workspace members. The read-only nature of the server and consistent categorization with other retrieval tools confirms this is a Read operation with low severity due to limited blast radius when misused.
From the tool's definition Tool name 'list_users' and description 'List all users in the Slack workspace' indicate a retrieval operation.
Risk signalsBulk/mass operation — affects multiple targets
Attacks that exploit this kind of access
List all 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 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.
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 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 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.
list_users is provided by the Slack MCP Server MCP server (mynghn/slack-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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