AI agents use set_value to create or update resources in MCP Server Redis — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP Server Redis environment.
set_value modifies or creates key-value pairs in Redis, which is a reversible operation (the value can be changed again or deleted). This makes it Write rather than Destructive. Severity is high because an AI agent with unrestricted access could overwrite critical application data, session states, or cached credentials in Redis.
From the tool's definition Tool name: 'set_value'; description: 'Set value for a Redis key'. This creates or modifies data in Redis reversibly.
Documented attack patterns abuse exactly the kind of access set_value gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Server Redis, and nothing reaches the server without passing your rules. This is the rule we recommend for set_value:
{
"version": "1",
"default": "deny",
"tools": {
"set_value": {
"limits": [
{
"counter": "set_value_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}set_value 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.
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Set value for a Redis key. It is categorised as a Write tool in the MCP Server Redis MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MCP Server Redis MCP server in PolicyLayer and add a rule for set_value: 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 MCP Server Redis. Nothing to install.
set_value 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 set_value 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 set_value. 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.
set_value is provided by the MCP Server Redis MCP server (prajwalnayak7/mcp-server-redis). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from MCP Server Redis, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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10 MCP Server Redis tools catalogued and risk-classified — across an index of 43,000+ MCP servers.