liara_set_env_var

THE RISK

Medium Risk

Why liara_set_env_var needs a policy

Setting environment variables modifies app configuration reversibly but can have significant operational impact (e.g., changing API keys, database credentials, feature flags). This is a Write operation (modifies data/configuration). Severity is high because incorrect env vars can break applications, expose secrets, or alter security posture, though the action itself is reversible and not destructive or financial.

From the tool's definition Tool name 'liara_set_env_var' and description 'Set a single environment variable for an app' indicate modification of application configuration.

Documented attack patterns abuse exactly the kind of access liara_set_env_var gives an agent:

POLICY

How to control liara_set_env_var

PolicyLayer is an MCP gateway — it sits between your AI agents and Liara MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for liara_set_env_var:

policy.json

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

liara_set_env_var 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.

Create a free account and register Liara MCP Server — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

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EXPLORE

Related tools and policies

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All 108 Liara MCP Server tools →

Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about liara_set_env_var

What does the liara_set_env_var tool do? +

Set a single environment variable for an app. It is categorised as a Write tool in the Liara 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 liara_set_env_var? +

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

What risk level is liara_set_env_var? +

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

Can I rate-limit liara_set_env_var? +

Yes. Add a rate_limit block to the liara_set_env_var 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 liara_set_env_var completely? +

Set action: deny in the PolicyLayer policy for liara_set_env_var. 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 liara_set_env_var? +

liara_set_env_var is provided by the Liara MCP Server MCP server (razavioo/liara-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Liara MCP Server tool call.

Start from Liara MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →