AI agents call cribl_listWorkerGroups to retrieve information from Cribl without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and enumerates existing worker groups with optional filtering. It performs no modifications, deletions, executions, or financial transactions. The filtering capability is a read-only parameter. The blast radius of misuse is minimal—an attacker gains visibility into deployment infrastructure but cannot alter or disrupt it.
From the tool's definition Tool name 'cribl_listWorkerGroups' and description 'Lists available worker groups' indicate a query/retrieval operation with no side effects.
Attacks that exploit this kind of access
Lists available worker groups in the Cribl deployment, optionally filtered by product type (stream, edge, search, or all). It is categorised as a Read tool in the Cribl MCP Server, which means it retrieves data without modifying state.
Register the Cribl MCP server in PolicyLayer and add a rule for cribl_listWorkerGroups: 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 Cribl. Nothing to install.
cribl_listWorkerGroups 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 cribl_listWorkerGroups 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 cribl_listWorkerGroups. 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.
cribl_listWorkerGroups is provided by the Cribl MCP server (pebbletek/cribl-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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