List all active Claude instances
AI agents call list_instances to retrieve information from Claude IPC MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves information about active Claude instances without side effects. It performs a simple enumeration or listing operation, which is characteristic of Read category tools. The severity is low because listing instances does not expose sensitive data operations, execute code, or modify state—it merely reports system status.
From the tool's definition Tool name 'list_instances' and description 'List all active Claude instances' indicate a query/retrieval operation with no modification or execution of external operations.
Attacks that exploit this kind of access
List all active Claude instances. It is categorised as a Read tool in the Claude IPC MCP MCP Server, which means it retrieves data without modifying state.
Register the Claude IPC MCP server in PolicyLayer and add a rule for list_instances: 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 Claude IPC MCP. Nothing to install.
list_instances 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_instances 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_instances. 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_instances is provided by the Claude IPC MCP server (jdez427/claude-ipc-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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