Remove and return members with highest scores. Args: key: The name of the key count: Number of members to pop (optional) Returns: Popped members with scores or error message
AI agents use sorted_set_popmax to create or update resources in AWS — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your AWS environment.
This tool modifies data by removing entries from a sorted set, which is a reversible write operation typical of Redis/cache operations. It is not Destructive (data can be recovered from backups or re-added), not Execute (no code/shell execution), and not Financial.
From the tool's definition Tool description states 'Remove and return members with highest scores' — the 'Remove' action is a reversible modification of data within a sorted set data structure. Arguments (key, count) identify which members to pop.
Documented attack patterns abuse exactly the kind of access sorted_set_popmax gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and AWS, and nothing reaches the server without passing your rules. This is the rule we recommend for sorted_set_popmax:
{
"version": "1",
"default": "deny",
"tools": {
"sorted_set_popmax": {
"limits": [
{
"counter": "sorted_set_popmax_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}sorted_set_popmax stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Remove and return members with highest scores. Args: key: The name of the key count: Number of members to pop (optional) Returns: Popped members with scores or error message. It is categorised as a Write tool in the AWS MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the AWS MCP server in PolicyLayer and add a rule for sorted_set_popmax: 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. Nothing to install.
sorted_set_popmax is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the sorted_set_popmax 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 sorted_set_popmax. 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.
sorted_set_popmax is provided by the AWS MCP server (@awslabs/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from AWS, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
300 AWS tools catalogued and risk-classified — across an index of 43,000+ MCP servers.