AI agents call listRuns to retrieve information from Terraform Registry MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The 'list' prefix in the tool name is characteristic of read-only operations that retrieve and enumerate existing data without modification. In the context of a Terraform Registry MCP server, 'listRuns' most likely retrieves a list of Terraform runs for inspection or monitoring purposes. The tool does not appear to create, modify, delete, or execute runs—it merely displays them.
From the tool's definition Tool name 'listRuns' indicates a listing/query operation. The broader server context describes 'provider lookups' and 'resource usage examples' as read-only operations.
Documented attack patterns abuse exactly the kind of access listRuns gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Terraform Registry MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for listRuns:
{
"version": "1",
"default": "deny",
"tools": {
"listRuns": {}
}
}listRuns is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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listRuns. It is categorised as a Read tool in the Terraform Registry MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Terraform Registry MCP Server MCP server in PolicyLayer and add a rule for listRuns: 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 Terraform Registry MCP Server. Nothing to install.
listRuns 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 listRuns 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 listRuns. 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.
listRuns is provided by the Terraform Registry MCP Server MCP server (thrashr888/terraform-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 24 Terraform Registry MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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24 Terraform Registry MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.