Get the length of string at path.
AI agents call json_strlen to retrieve information from Amazon MQ MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries or retrieves information (the length of a string) from a JSON structure. It has no side effects, does not modify data, execute code, or trigger external operations. It is purely informational, matching the 'Read' category definition: 'retrieves or queries data; no side effects.'
From the tool's definition Tool name 'json_strlen' and description 'Get the length of string at path' indicate a read-only operation that retrieves metadata about a string value without modifying data.
Attacks that exploit this kind of access
Get the length of string at path. It is categorised as a Read tool in the Amazon MQ MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Amazon MQ MCP Server MCP server in PolicyLayer and add a rule for json_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 Amazon MQ MCP Server. Nothing to install.
json_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 json_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 json_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.
json_strlen is provided by the Amazon MQ MCP Server MCP server (awslabs.amazon-mq-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.