Lists all indices in OpenSearch.
AI agents call ListIndexTool to retrieve information from Opensearch without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool only retrieves and enumerates indices from OpenSearch, performing a non-destructive read operation. It has no capability to modify, delete, or execute operations. The blast radius of misuse is minimal—an attacker could enumerate the structure of the cluster but cannot access data, modify configurations, or trigger operations. This is a standard metadata discovery operation classified as Read.
From the tool's definition Tool name 'ListIndexTool' and description 'Lists all indices in OpenSearch' indicates a query operation that retrieves metadata without modification or side effects.
Attacks that exploit this kind of access
Lists all indices in OpenSearch. It is categorised as a Read tool in the Opensearch MCP Server, which means it retrieves data without modifying state.
Register the Opensearch MCP server in PolicyLayer and add a rule for ListIndexTool: 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 Opensearch. Nothing to install.
ListIndexTool 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 ListIndexTool 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 ListIndexTool. 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.
ListIndexTool is provided by the Opensearch MCP server (rithinpullela/opensearch-mcp-server). 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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