List public channels in the Mattermost workspace with pagination
AI agents call mattermost_list_channels to retrieve information from Mattermost 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 and queries channel data from a Mattermost workspace without creating, modifying, deleting, or executing any operations. It is a standard read operation that returns existing data. The blast radius of misuse is minimal—an AI agent could enumerate channels but cannot cause data loss, modify content, or execute external actions.
From the tool's definition Tool name and description indicate it 'List public channels' and retrieves channel information 'with pagination'. The verb 'list' and the read-only nature of retrieving channel metadata without modification.
Documented attack patterns abuse exactly the kind of access mattermost_list_channels gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mattermost MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for mattermost_list_channels:
{
"version": "1",
"default": "deny",
"tools": {
"mattermost_list_channels": {}
}
}mattermost_list_channels is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List public channels in the Mattermost workspace with pagination. It is categorised as a Read tool in the Mattermost MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Mattermost MCP Server 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 MCP Server. 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 MCP server (pvev/mattermost-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 9 Mattermost MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
9 Mattermost MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.