🔍 [SAFE] Get distinct values for a field (useful for understanding what values exist in a column). May return many values for high-cardinality fields. Risk: None - read-only, but may return large results.
AI agents call get_field_values to retrieve information from Metabase MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries data from Metabase without modifying, deleting, or executing any operations. It is a straightforward read operation that returns information about column values. The only minor consideration is that it may return large result sets, but this does not elevate it beyond the Read category. The confidence is high due to the explicit safety designation in the description.
From the tool's definition Tool description explicitly states 'Get distinct values for a field' and 'read-only'. The [SAFE] tag and 'Risk: None' further confirm this is a retrieval operation with no side effects.
Attacks that exploit this kind of access
🔍 [SAFE] Get distinct values for a field (useful for understanding what values exist in a column). May return many values for high-cardinality fields. Risk: None - read-only, but may return large results. It is categorised as a Read tool in the Metabase MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Metabase 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 Metabase 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 Metabase MCP Server MCP server (mikela92/metabase-mcp-mab). 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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