AI agents call list to retrieve information from tmux-claude MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries the state of active Claude instances and returns a list—a read-only information retrieval operation. There are no side effects, no data modification, no code execution, and no destructive actions. The blast radius of misuse is minimal; an attacker could learn what instances are running but cannot manipulate them directly through this tool alone.
From the tool's definition Tool name 'list' with description 'List all active Claude instances' performs retrieval of information about running processes/instances with no modification or execution of external operations.
Documented attack patterns abuse exactly the kind of access list gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and tmux-claude MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for list:
{
"version": "1",
"default": "deny",
"tools": {
"list": {}
}
}list is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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List all active Claude instances. It is categorised as a Read tool in the tmux-claude MCP Server MCP Server, which means it retrieves data without modifying state.
Register the tmux-claude MCP Server MCP server in PolicyLayer and add a rule for list: 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 tmux-claude MCP Server. Nothing to install.
list 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 list 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 list. 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.
list is provided by the tmux-claude MCP Server MCP server (michael-abdo/tmux-claude-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from tmux-claude MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
26 tmux-claude MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.