Get the number of keys in the object at path.
AI agents call json_objlen to retrieve information from Amazon ElastiCache Memcached 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 metadata about a cached object (the key count) without side effects. It is a non-destructive read operation against ElastiCache Memcached, similar to inspection or introspection commands. No data is created, modified, or deleted; no code is executed; no financial transaction occurs.
From the tool's definition Tool description states 'Get the number of keys in the object at path' — a retrieval operation that returns a count without modifying data.
Attacks that exploit this kind of access
Get the number of keys in the object at path. It is categorised as a Read tool in the Amazon ElastiCache Memcached MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Amazon ElastiCache Memcached MCP Server MCP server in PolicyLayer and add a rule for json_objlen: 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 ElastiCache Memcached MCP Server. Nothing to install.
json_objlen 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_objlen 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_objlen. 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_objlen is provided by the Amazon ElastiCache Memcached MCP Server MCP server (awslabs.memcached-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.