AI agents call cmux_tree 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.
This tool only reads and displays the hierarchical structure of terminal windows, workspaces, panes, and surfaces. It has no side effects and performs no modifications.
From the tool's definition Print the window > workspace > pane > surface tree
Attacks that exploit this kind of access
Print the window > workspace > pane > surface tree. 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_tree: 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_tree 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_tree 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_tree. 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_tree 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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