Get the most common values for a specific field.
AI agents call get_field_values to retrieve information from OpenSearch Logs MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only query operation against OpenSearch logs to retrieve statistical data about field values. It has no side effects, does not execute code, and does not modify or delete data. The operation is a passive data retrieval that returns information already present in the logs, consistent with other sibling tools like get_sample_log and search functions on this server.
From the tool's definition Tool description states 'Get the most common values for a specific field' with no modification, deletion, or execution capability mentioned. It retrieves aggregated log data from OpenSearch indexes.
Attacks that exploit this kind of access
Get the most common values for a specific field. It is categorised as a Read tool in the OpenSearch Logs MCP Server MCP Server, which means it retrieves data without modifying state.
Register the OpenSearch Logs MCP Server MCP server in PolicyLayer and add a rule for get_field_values: 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 Logs MCP Server. Nothing to install.
get_field_values 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 get_field_values 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 get_field_values. 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.
get_field_values is provided by the OpenSearch Logs MCP Server MCP server (luis-dominguez-stori/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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