Get length of field value in hash.
AI agents call hash_strlen to retrieve information from AWS IoT SiteWise MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool performs a read-only operation—it retrieves metadata (string length) about an existing hash field value. It has no side effects, does not execute code, and does not modify, delete, or create data. It fits the Read category (retrieves or queries data with no side effects) and poses minimal security risk if misused by an AI agent, as the worst outcome is information disclosure of field lengths.
From the tool's definition Tool name 'hash_strlen' and description 'Get length of field value in hash' indicate a retrieval operation that queries the length of a hash field without modifying data.
Attacks that exploit this kind of access
Get length of field value in hash. It is categorised as a Read tool in the AWS IoT SiteWise MCP Server MCP Server, which means it retrieves data without modifying state.
Register the AWS IoT SiteWise MCP Server MCP server in PolicyLayer and add a rule for hash_strlen: 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.
hash_strlen 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 hash_strlen 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 hash_strlen. 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.
hash_strlen 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.