create_or_update_file

THE RISK

Medium Risk

Why create_or_update_file needs a policy

This tool creates or modifies file content in a repository, which is reversible (can be overwritten or reverted via git operations). It is not destructive (no deletion), not financial, and not execute (no arbitrary code execution specified). The medium severity reflects that unintended file modifications could break code or corrupt repository state, but can be recovered through version control.

From the tool's definition Tool description states 'Create or update a single file in a GitHub repository' — both creation and modification of files are reversible write operations.

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

POLICY

How to control create_or_update_file

PolicyLayer is an MCP gateway — it sits between your AI agents and Claude TypeScript MCP Servers, and nothing reaches the server without passing your rules. This is the rule we recommend for create_or_update_file:

policy.json

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

create_or_update_file 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 Claude TypeScript MCP Servers — 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

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All 84 Claude TypeScript MCP Servers tools →

Write tools on other servers

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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 create_or_update_file

What does the create_or_update_file tool do? +

Create or update a single file in a GitHub repository. It is categorised as a Write tool in the Claude TypeScript MCP Servers MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_or_update_file? +

Register the Claude TypeScript MCP Servers MCP server in PolicyLayer and add a rule for create_or_update_file: 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 Claude TypeScript MCP Servers. Nothing to install.

What risk level is create_or_update_file? +

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

Can I rate-limit create_or_update_file? +

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

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

create_or_update_file is provided by the Claude TypeScript MCP Servers MCP server (ukkz/claude-ts-mcps). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Claude TypeScript MCP Servers tool call.

Start from Claude TypeScript MCP Servers, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →