Add a value to a Redis set with an optional expiration time. Args: name: The Redis set key. value: The value to add to the set. expire_seconds: Optional; time in seconds after which the set should expire. Returns: A success message or an error message.
AI agents use sadd 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.
The sadd tool adds data to a Redis set, which is a reversible data modification operation. This fits the Write category as it creates or modifies data without irreversible destruction. Severity is medium because uncontrolled writes could fill Redis memory or corrupt application state, but the data remains recoverable (via delete or key expiration).
From the tool's definition Tool description states "Add a value to a Redis set" - this creates or modifies data in Redis. The parameters include a required value to add and optional expiration, confirming the write operation.
Documented attack patterns abuse exactly the kind of access sadd gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Redis MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for sadd:
{
"version": "1",
"default": "deny",
"tools": {
"sadd": {
"limits": [
{
"counter": "sadd_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}sadd 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.
Add a value to a Redis set with an optional expiration time. Args: name: The Redis set key. value: The value to add to the set. expire_seconds: Optional; time in seconds after which the set should expire. Returns: A success message or an error message. 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.
Register the Redis MCP Server MCP server in PolicyLayer and add a rule for sadd: 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.
sadd 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 sadd 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 sadd. 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.
sadd is provided by the Redis MCP Server MCP server (redis/mcp-redis). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 53 Redis MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
53 Redis MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.