List public or pre-defined channels in the workspace with pagination
AI agents call slack_list_channels to retrieve information from Server Puppeteer without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves channel information from Slack without creating, modifying, or deleting any data. It is a straightforward read operation that lists existing channels. The blast radius of misuse is minimal—an agent could enumerate channels but cannot cause damage, financial loss, or irreversible changes. Severity is low because channel listings are typically non-sensitive metadata in most Slack workspaces.
From the tool's definition Tool name and description indicate it 'List public or pre-defined channels' which is a retrieval operation with no side effects. The action is non-destructive data querying.
Attacks that exploit this kind of access
List public or pre-defined channels in the workspace with pagination. It is categorised as a Read tool in the Server Puppeteer MCP Server, which means it retrieves data without modifying state.
Register the Server Puppeteer MCP server in PolicyLayer and add a rule for slack_list_channels: 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 Server Puppeteer. Nothing to install.
slack_list_channels 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_channels 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_channels. 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_channels is provided by the Server Puppeteer MCP server (@hisma/server-puppeteer). 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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