AI agents call list_traces to retrieve information from Storage without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves observability/diagnostic data from Google Cloud Trace without creating, modifying, deleting, or executing operations. It is purely informational in nature, making it a Read category tool with low severity since it only accesses trace metadata and does not affect system state or data.
From the tool's definition Tool description states 'retrieve and examine distributed traces' with no modification capability. The verb 'retrieve' and the purpose of examining traces (observability data) indicate read-only querying.
Attacks that exploit this kind of access
Use this as the primary tool to retrieve and examine distributed traces from Google Cloud Trace. Traces provide a detailed view of the path of a request as it travels through your application. It is categorised as a Read tool in the Storage MCP Server, which means it retrieves data without modifying state.
Register the Storage MCP server in PolicyLayer and add a rule for list_traces: 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 Storage. Nothing to install.
list_traces 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_traces 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_traces. 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_traces is provided by the Storage MCP server (@google-cloud/storage-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.