tmux_kill_session
AI agents call tmux_kill_session to permanently remove resources in TmuxControlLib MCP Server — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
In tmux, 'kill-session' terminates a session and all its windows, panes, and running processes. This is irreversible — any unsaved work or running processes are destroyed. The description is empty, but the tool name strongly implies destructive action consistent with the tmux kill-session command. Severity is high because it can destroy running processes and terminal state across an entire session.
From the tool's definition Tool name 'tmux_kill_session' — 'kill' in the context of tmux means terminating/destroying a session, which is irreversible (all processes and state in that session are lost).
Attacks that exploit this kind of access
tmux_kill_session. It is categorised as a Destructive tool in the TmuxControlLib MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the TmuxControlLib MCP Server MCP server in PolicyLayer and add a rule for tmux_kill_session: 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 TmuxControlLib MCP Server. Nothing to install.
tmux_kill_session is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the tmux_kill_session 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 tmux_kill_session. 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.
tmux_kill_session is provided by the TmuxControlLib MCP Server MCP server (jbwinters/tmuxcontrollib). 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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