pyenv

THE RISK

High Risk

Why pyenv needs a policy

Managing Python versions via pyenv involves executing pyenv commands that can install, switch, or configure Python environments. This triggers external operations and system changes. The description is brief but pyenv management implies command execution with potential environment-wide effects.

From the tool's definition Manages Python versions via pyenv

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

POLICY

How to control pyenv

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "pyenv": {
      "limits": [
        {
          "counter": "pyenv_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

pyenv stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

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

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Lint tools

Destructive clean Runs dotnet clean to remove build outputs and returns structured results. Destructive remove Runs Destructive reset Resets the current HEAD to a specified state. Supports soft, mixed, hard, merge, and keep Destructive secret-delete Deletes a repository, organization, or environment GitHub Actions secret. Destructive tag Manages git tags. Supports list (default), create, and delete actions. List returns struct Destructive variable-delete Deletes a repository, organization, or environment GitHub Actions variable. Destructive workspace Manages Terraform workspaces: list, select, create, or delete workspaces. Destructive package-clean Cleans Swift package build artifacts and returns structured result.

All 202 Lint tools →

Execute tools on other servers

Android Forensics ADB MCP Server adb_shell_command EMBA-MCP run_emba_scan Frida Game Hacking MCP remove_breakpoint Procmon request_elevation

Go deeper

Govern code and CI agents → Branch allowlists, approval on merges, and rate caps on the build and pipeline tools agents trigger.
High-risk tools in Lint → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →
PolicyLayer vs alternatives → How deterministic, per-call MCP policy compares with gateways, identity layers, and authorisation platforms.

FAQ

Questions about pyenv

What does the pyenv tool do? +

Manages Python versions via pyenv. It is categorised as a Execute tool in the Lint MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on pyenv? +

Register the Lint MCP server in PolicyLayer and add a rule for pyenv: 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 Lint. Nothing to install.

What risk level is pyenv? +

pyenv is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit pyenv? +

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

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

pyenv is provided by the Lint MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Lint tool call.

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

CHECK YOUR STACK →