pm-ls · Python MCP: Risk & Policy

WHAT IT DOES

What pm-ls does on Python

AI agents invoke pm-ls 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.

WHY IT NEEDS A POLICY

Why pm-ls needs a policy

The description is truncated to just 'Runs', but in context of the server (which wraps pip/uv/package management tools) and the 'pm-ls' name suggesting a package manager list command, this likely executes a package manager list command. Execution of external CLI tools warrants Execute category. Confidence is moderate due to the uninformative truncated description.

From the tool's definition Tool name 'pm-ls' and server description mentions 'pip, uv' package managers; 'Runs' suggests execution of an external command

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

pm-ls Rate-limited

pm-ls 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "pm-ls": {
      "limits": [
        {
          "counter": "pm-ls_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Python, so you can run agents against it safely.

FAQ

Questions about pm-ls

What does the pm-ls tool do? +

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

How do I enforce a policy on pm-ls? +

Register the Python MCP server in PolicyLayer and add a rule for pm-ls: 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 Python. Nothing to install.

What risk level is pm-ls? +

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

Can I rate-limit pm-ls? +

Yes. Add a rate_limit block to the pm-ls 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 pm-ls completely? +

Set action: deny in the PolicyLayer policy for pm-ls. 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 pm-ls? +

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

// THE FULL RECORD

pm-ls is one line of Python's registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

Teams ship this data inside their own products. See what a licence covers →