Medium Risk

string_set

Set string value. Args: key: The name of the key value: The value to set ex: Expire time in seconds px: Expire time in milliseconds nx: Only set if key does not exist xx: Only set if key exists keepttl: Retain the time to live associated with the key Returns: Suc...

Part of the Awslabs Valkey MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.

AI agents use string_set to create or modify resources in Awslabs Valkey. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.

Without a policy, an AI agent could call string_set repeatedly, creating or modifying resources faster than any human could review. Intercept's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Awslabs Valkey.

Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.

amazon-elasticache-memorydb-valkey-mcp-server.yaml
tools:
  string_set:
    rules:
      - action: allow
        rate_limit:
          max: 30
          window: 60

See the full Awslabs Valkey policy for all 105 tools.

Tool Name string_set
Category Write
Risk Level Medium

View all 105 tools →

Agents calling write-class tools like string_set have been implicated in these attack patterns. Read the full case and prevention policy for each:

Browse the full MCP Attack Database →

Other tools in the Write risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.

What does the string_set tool do? +

Set string value. Args: key: The name of the key value: The value to set ex: Expire time in seconds px: Expire time in milliseconds nx: Only set if key does not exist xx: Only set if key exists keepttl: Retain the time to live associated with the key Returns: Success message or error message. It is categorised as a Write tool in the Awslabs Valkey MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on string_set? +

Add a rule in your Intercept YAML policy under the tools section for string_set. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Awslabs Valkey MCP server.

What risk level is string_set? +

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

Can I rate-limit string_set? +

Yes. Add a rate_limit block to the string_set rule in your Intercept 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 string_set completely? +

Set action: deny in the Intercept policy for string_set. 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 string_set? +

string_set is provided by the Awslabs Valkey MCP server (awslabs.valkey-mcp-server). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Let agents act without letting them run wild.

Deterministic policy on every MCP tool call. Per-identity grants. Full audit log.

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