AI agents call cmux_list_groups to retrieve information from Cmux without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
cmux_list_groups retrieves and lists existing workspace groups in JSON format. This is a read-only operation that queries state without modifying, deleting, or executing code. No irreversible changes or external operations are triggered. The low severity reflects minimal blast radius if misused by an agent.
From the tool's definition Tool name and description indicate it 'List[s] sidebar workspace groups as JSON' — a query operation with no side effects.
Attacks that exploit this kind of access
List sidebar workspace groups as JSON, including each group. It is categorised as a Read tool in the Cmux MCP Server, which means it retrieves data without modifying state.
Register the Cmux MCP server in PolicyLayer and add a rule for cmux_list_groups: 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 Cmux. Nothing to install.
cmux_list_groups 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 cmux_list_groups 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 cmux_list_groups. 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.
cmux_list_groups is provided by the Cmux MCP server (puchkoff/cmux-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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