add_issue_comment · Mcp Github MCP: Risk & Policy

WHAT IT DOES

What add_issue_comment does on Mcp Github

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

WHY IT NEEDS A POLICY

Why add_issue_comment needs a policy

This tool creates new data (a comment) in a reversible manner. It does not delete, execute arbitrary code, move money, or trigger external operations. While it modifies a repository's issue state, the action is non-destructive and can be undone.

From the tool's definition Tool name is 'add_issue_comment' and description states 'Add a comment to an existing issue' — this creates new content (a comment) that modifies the issue thread but is reversible (comments can be edited or deleted).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_issue_comment Rate-limited

add_issue_comment 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": {
    "add_issue_comment": {
      "limits": [
        {
          "counter": "add_issue_comment_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 Mcp Github, so you can run agents against it safely.

FAQ

Questions about add_issue_comment

What does the add_issue_comment tool do? +

Add a comment to an existing issue. It is categorised as a Write tool in the Mcp Github MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_issue_comment? +

Register the Mcp Github MCP server in PolicyLayer and add a rule for add_issue_comment: 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 Mcp Github. Nothing to install.

What risk level is add_issue_comment? +

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

Can I rate-limit add_issue_comment? +

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

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

add_issue_comment is provided by the Mcp Github MCP server (@missionsquad/mcp-github). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.