Lists workspace channels by type (public, private, DMs, group DMs) with optional popularity sorting. Supports pagination.
AI agents call channels_list 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 channel metadata without creating, modifying, deleting, or executing any operations. It has read-only semantics. Severity is low because channel names and types are typically non-sensitive metadata in Slack workspaces, and this operation has no side effects or blast radius beyond information disclosure of already-accessible workspace structure.
From the tool's definition Tool lists workspace channels by type with optional popularity sorting and pagination support. The description contains only retrieval verbs: 'lists' and 'supports pagination.' No modification, deletion, or execution of operations is indicated.
Attacks that exploit this kind of access
Lists workspace channels by type (public, private, DMs, group DMs) with optional popularity sorting. Supports pagination. 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 channels_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 Slack MCP Server. Nothing to install.
channels_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 channels_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 channels_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.
channels_list is provided by the Slack MCP Server MCP server (oregpt/agenticledger_mcp_slack). 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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