github_contents_write · Promethean OS MCP: Risk & Policy

WHAT IT DOES

What github_contents_write does on Promethean OS MCP

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

WHY IT NEEDS A POLICY

Why github_contents_write needs a policy

This tool performs write operations on a remote GitHub repository by creating or updating files. While file modifications are theoretically reversible (can be undone via git), the operation commits changes that affect a shared repository, potentially impacting collaborators and CI/CD pipelines.

From the tool's definition 'Create or update a file via the GitHub contents API' - the tool explicitly creates or modifies data (file contents) through GitHub's API, which is reversible.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

github_contents_write Rate-limited

github_contents_write 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": {
    "github_contents_write": {
      "limits": [
        {
          "counter": "github_contents_write_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 Promethean OS MCP, so you can run agents against it safely.

FAQ

Questions about github_contents_write

What does the github_contents_write tool do? +

Create or update a file via the GitHub contents API with automatic base64 encoding. It is categorised as a Write tool in the Promethean OS MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on github_contents_write? +

Register the Promethean OS MCP server in PolicyLayer and add a rule for github_contents_write: 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 Promethean OS MCP. Nothing to install.

What risk level is github_contents_write? +

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

Can I rate-limit github_contents_write? +

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

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

github_contents_write is provided by the Promethean OS MCP server (octave-commons/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.