generate_pr_description · Pr MCP: Risk & Policy

WHAT IT DOES

What generate_pr_description does on Pr

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

WHY IT NEEDS A POLICY

Why generate_pr_description needs a policy

An AI agent can call generate_pr_description faster than any human can review — one bad instruction and it creates or modifies resources in Pr by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

generate_pr_description Rate-limited

generate_pr_description 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": {
    "generate_pr_description": {
      "limits": [
        {
          "counter": "generate_pr_description_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 Pr, so you can run agents against it safely.

FAQ

Questions about generate_pr_description

What does the generate_pr_description tool do? +

⚠️ CRITICAL: This tool returns an ANALYSIS PROMPT for YOU (Claude) to generate a description, NOT a final description. OUTPUT: You receive comprehensive context (project type, commits, files, diff sample) formatted as a detailed prompt with specific instructions. YOUR JOB: Analyze that context and generate an intelligent, well-structured PR description. The prompt includes format requirements (What/Why/How/Impact sections), language preferences (FR/EN), and style guidelines. YOU must read it, understand the changes, and write a clear description ready for GitHub. DO NOT return the prompt - generate YOUR description. Use when creating PR or when user asks for PR description. The generated description should then be passed to create_pr or create_pr_complete tools. It is categorised as a Write tool in the Pr MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on generate_pr_description? +

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

What risk level is generate_pr_description? +

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

Can I rate-limit generate_pr_description? +

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

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

generate_pr_description is provided by the Pr MCP server (valentin-harrang/pr-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.