Trim stream to specified length.
AI agents call stream_trim to permanently remove resources in AWS IoT SiteWise MCP Server — typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Trimming a stream permanently removes older entries beyond the specified length. This is an irreversible data loss operation similar to purge or delete, qualifying as Destructive. Severity is high because misuse could permanently delete significant amounts of IoT time-series data from SiteWise streams.
From the tool's definition 'Trim stream to specified length' — trimming a stream removes/truncates data that cannot be recovered, making it an irreversible destructive operation.
Attacks that exploit this kind of access
Trim stream to specified length. It is categorised as a Destructive tool in the AWS IoT SiteWise MCP Server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the AWS IoT SiteWise MCP Server MCP server in PolicyLayer and add a rule for stream_trim: 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 AWS IoT SiteWise MCP Server. Nothing to install.
stream_trim is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the stream_trim 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 stream_trim. 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.
stream_trim is provided by the AWS IoT SiteWise MCP Server MCP server (awslabs.aws-iot-sitewise-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.