pr-update · Python MCP: Risk & Policy

WHAT IT DOES

What pr-update does on Python

AI agents use pr-update to create or update resources in Python — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Python environment.

WHY IT NEEDS A POLICY

Why pr-update needs a policy

This tool modifies pull request properties reversibly (updates to metadata can be reverted by subsequent calls). It does not delete data, execute code, or move money. The capability to change PR base branch, title, and body introduces moderate risk if misused by an agent, as it could alter development workflows or mislead reviewers, but changes are not irreversible.

From the tool's definition Tool description states it "Updates pull request metadata (title, body, labels, assignees, reviewers, milestone, base branch, projects)" - these are modification operations on PR data.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

pr-update Rate-limited

pr-update 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "pr-update": {
      "limits": [
        {
          "counter": "pr-update_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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 pr-update

What does the pr-update tool do? +

Updates pull request metadata (title, body, labels, assignees, reviewers, milestone, base branch, projects). Returns structured data with PR number and URL. It is categorised as a Write tool in the Python MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on pr-update? +

Register the Python MCP server in PolicyLayer and add a rule for pr-update: 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 pr-update? +

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

Can I rate-limit pr-update? +

Yes. Add a rate_limit block to the pr-update 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 pr-update completely? +

Set action: deny in the PolicyLayer policy for pr-update. 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 pr-update? +

pr-update 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.