lpush · Redis MCP Server MCP: Risk & Policy

WHAT IT DOES

What lpush does on Redis MCP Server

AI agents use lpush to create or update resources in Redis MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Redis MCP Server environment.

WHY IT NEEDS A POLICY

Why lpush needs a policy

The lpush operation creates or modifies data in a reversible manner (the pushed value can be removed with lpop or lrem). It is not destructive since the original list data is preserved and the operation can be undone. It is not Execute-level since it doesn't run arbitrary code or trigger external operations—it's a simple data modification.

From the tool's definition Tool name is 'lpush' which performs a list push operation. Description states 'Push a value onto the left of a Redis list and optionally set an expiration time.' This modifies data by adding/inserting elements into an existing list structure.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

lpush Rate-limited

lpush 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "lpush": {
      "limits": [
        {
          "counter": "lpush_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Redis MCP Server, so you can run agents against it safely.

FAQ

Questions about lpush

What does the lpush tool do? +

Push a value onto the left of a Redis list and optionally set an expiration time. It is categorised as a Write tool in the Redis MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on lpush? +

Register the Redis MCP Server MCP server in PolicyLayer and add a rule for lpush: 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 Redis MCP Server. Nothing to install.

What risk level is lpush? +

lpush is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit lpush? +

Yes. Add a rate_limit block to the lpush 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.

How do I block lpush completely? +

Set action: deny in the PolicyLayer policy for lpush. 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.

What MCP server provides lpush? +

lpush is provided by the Redis MCP Server MCP server (yuchenhui/mcp-redis). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.