createBranch · GitHub MCP Server MCP: Risk & Policy

WHAT IT DOES

What createBranch does on GitHub MCP Server

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

WHY IT NEEDS A POLICY

Why createBranch needs a policy

Creating a branch is a write operation that adds new structure to a repository. It is reversible (branches can be deleted), so it does not qualify as Destructive. The blast radius is medium because unauthorized branch creation could pollute the repository namespace, interfere with workflows, or serve as a staging point for malicious changes, but the impact is containable and does not directly delete data or execute…

From the tool's definition Tool name 'createBranch' and description 'Create a new branch in a GitHub repository' indicate a reversible creation operation that modifies repository structure.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

createBranch Rate-limited

createBranch 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": {
    "createBranch": {
      "limits": [
        {
          "counter": "createbranch_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 GitHub MCP Server, so you can run agents against it safely.

FAQ

Questions about createBranch

What does the createBranch tool do? +

Create a new branch in a GitHub repository. It is categorised as a Write tool in the GitHub MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on createBranch? +

Register the GitHub MCP Server MCP server in PolicyLayer and add a rule for createBranch: 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 GitHub MCP Server. Nothing to install.

What risk level is createBranch? +

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

Can I rate-limit createBranch? +

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

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

createBranch is provided by the GitHub MCP Server MCP server (j-nowcow/github-mcp-practice). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.