fork_repository

THE RISK

Medium Risk

Why fork_repository needs a policy

Forking creates a new repository under the user's or specified organization's account—a reversible Write operation. While it consumes resources and modifies the account structure, it does not delete data, execute arbitrary code, or move money. The severity is medium because the blast radius includes account quota consumption and potential quota exhaustion, but the operation is reversible (the fork can be deleted).

From the tool's definition Tool name 'fork_repository' and description 'Fork a GitHub repository to your account or specified organization' indicate creation of a new repository resource as a copy of an existing one.

Documented attack patterns abuse exactly the kind of access fork_repository gives an agent:

POLICY

How to control fork_repository

PolicyLayer is an MCP gateway — it sits between your AI agents and GitHub MCP Server Plus, and nothing reaches the server without passing your rules. This is the rule we recommend for fork_repository:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "fork_repository": {
      "limits": [
        {
          "counter": "fork_repository_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

fork_repository 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.

Create a free account and register GitHub MCP Server Plus — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More GitHub MCP Server Plus tools

Write add_issue_comment Add a comment to an existing issue Write create_branch Create a new branch in a GitHub repository Write create_issue Create a new issue in a GitHub repository Write create_or_update_file Create or update a single file in a GitHub repository Write create_pull_request Create a new pull request in a GitHub repository Write create_repository Create a new GitHub repository in your account Write push_files_content Push multiple files with direct content to a GitHub repository in a single commit Write push_files_from_path Push multiple files from filesystem paths to a GitHub repository in a single commit

All 18 GitHub MCP Server Plus tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about fork_repository

What does the fork_repository tool do? +

Fork a GitHub repository to your account or specified organization. It is categorised as a Write tool in the GitHub MCP Server Plus MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on fork_repository? +

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

What risk level is fork_repository? +

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

Can I rate-limit fork_repository? +

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

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

fork_repository is provided by the GitHub MCP Server Plus MCP server (phialsbasement/mcp-github-server-plus). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every GitHub MCP Server Plus tool call.

Start from GitHub MCP Server Plus, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →