# pyenv

Manages Python versions via pyenv.

Agent View of the PolicyLayer registry record for `pyenv`. HTML page: https://policylayer.com/tools/io-github-dave-london-pare-python/pyenv

## Facts

- Tool: `pyenv`
- Server: Python (`Dave-London/Pare`) — https://policylayer.com/tools/io-github-dave-london-pare-python.md
- Homepage: https://github.com/Dave-London/Pare
- Risk category: Execute (High risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 8 (1 required)
- Recommended policy verdict: Rate-limited

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `path` | string | no | Working directory |
| `force` | boolean | no | Force reinstallation of an already installed version (--force) |
| `unset` | boolean | no | Clear local/global version setting (--unset) |
| `action` | string | yes | The pyenv action to perform |
| `command` | string | no | Command name for `which` action (e.g. python, pip) |
| `compact` | boolean | no | Prefer compact output |
| `version` | string | no | Python version string (required for install/uninstall/local/global, e.g. '3.12.0') |
| `skipExisting` | boolean | no | Skip installation if version is already installed (--skip-existing) |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "pyenv",
    "arguments": {
      "action": "<action>"
    }
  }
}
```

## Why pyenv is rated High

Managing Python versions via pyenv involves executing shell commands to install, switch, or configure Python runtimes. This can affect the system's Python environment broadly, and misuse could install arbitrary Python versions or alter the active runtime, impacting all dependent processes. Since it runs external tooling (pyenv) and has system-level effects, Execute is the appropriate category.

From the tool's own definition: "Manages Python versions via pyenv"

Risk signals: Accepts file system path (path)

## Use case

AI agents invoke pyenv to trigger actions in Python. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Python:

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

## Other tools on Python (13)

- `conda` — Execute — https://policylayer.com/tools/io-github-dave-london-pare-python/conda.md
- `mypy` — Execute — https://policylayer.com/tools/io-github-dave-london-pare-python/mypy.md
- `pip-install` — Execute — https://policylayer.com/tools/io-github-dave-london-pare-python/pip-install.md
- `poetry` — Execute — https://policylayer.com/tools/io-github-dave-london-pare-python/poetry.md
- `pytest` — Execute — https://policylayer.com/tools/io-github-dave-london-pare-python/pytest.md
- `ruff-check` — Execute — https://policylayer.com/tools/io-github-dave-london-pare-python/ruff-check.md
- `uv-install` — Execute — https://policylayer.com/tools/io-github-dave-london-pare-python/uv-install.md
- `uv-run` — Execute — https://policylayer.com/tools/io-github-dave-london-pare-python/uv-run.md
- `black` — Read — https://policylayer.com/tools/io-github-dave-london-pare-python/black.md
- `pip-audit` — Read — https://policylayer.com/tools/io-github-dave-london-pare-python/pip-audit.md
- `pip-list` — Read — https://policylayer.com/tools/io-github-dave-london-pare-python/pip-list.md
- `pip-show` — Read — https://policylayer.com/tools/io-github-dave-london-pare-python/pip-show.md
- `ruff-format` — Read — https://policylayer.com/tools/io-github-dave-london-pare-python/ruff-format.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=io-github-dave-london-pare-python · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/io-github-dave-london-pare-python