list_columns
AI agents call list_columns to retrieve information from Looker MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool retrieves column metadata from Looker's semantic model without modifying, executing, or deleting anything. While the description is empty, the name strongly indicates a list/query operation (Read category). Severity is low because column metadata is typically non-sensitive structural information.
From the tool's definition Tool name is 'list_columns' which indicates a retrieval operation. The server description mentions 'querying the semantic model' as a core capability, and 'list_*' operations are inherently read-only information retrieval operations.
Attacks that exploit this kind of access
list_columns. It is categorised as a Read tool in the Looker MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Looker MCP Server MCP server in PolicyLayer and add a rule for list_columns: 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 Looker MCP Server. Nothing to install.
list_columns 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_columns 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_columns. 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_columns is provided by the Looker MCP Server MCP server (ultrathink-solutions/looker-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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