List channels in the Mattermost workspace. By default lists public team channels. Set include_private=true to get all channels including private channels and direct messages (DMs).
AI agents call mattermost_list_channels to retrieve information from Mattermost without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries channel data from the Mattermost workspace. It has no capability to create, modify, delete, or execute operations—it only enumerates existing channels. Even though it can include private channels and DMs when a parameter is set, this is still purely a read operation returning existing data.
From the tool's definition Tool name 'mattermost_list_channels' and description 'List channels' indicate a retrieval operation with no side effects. The description explicitly states it 'lists' channels without any capability to modify, delete, or execute actions.
Attacks that exploit this kind of access
List channels in the Mattermost workspace. By default lists public team channels. Set include_private=true to get all channels including private channels and direct messages (DMs). It is categorised as a Read tool in the Mattermost MCP Server, which means it retrieves data without modifying state.
Register the Mattermost MCP server in PolicyLayer and add a rule for mattermost_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 Mattermost. Nothing to install.
mattermost_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 mattermost_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 mattermost_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.
mattermost_list_channels is provided by the Mattermost MCP server (@conarti/mattermost-mcp). 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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