infracost_comment · Infracost MCP Server MCP: Risk & Policy

WHAT IT DOES

What infracost_comment does on Infracost MCP Server

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

WHY IT NEEDS A POLICY

Why infracost_comment needs a policy

This tool creates and modifies comments on pull requests, which are reversible write operations. While it interacts with external systems, it does not delete data (Destructive), move money (Financial), or execute arbitrary code (Execute). The impact is scoped to adding or updating cost estimate comments.

From the tool's definition Tool description states it will 'Post cost estimate comments to pull requests' and 'Automatically updates existing comments', which are write operations that create or modify data on external systems (GitHub, GitLab, Azure Repos, or Bitbucket).

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

infracost_comment Rate-limited

infracost_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": {
    "infracost_comment": {
      "limits": [
        {
          "counter": "infracost_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 Infracost MCP Server, so you can run agents against it safely.

FAQ

Questions about infracost_comment

What does the infracost_comment tool do? +

Post cost estimate comments to pull requests on GitHub, GitLab, Azure Repos, or Bitbucket. Automatically updates existing comments. Requires infracost CLI to be installed and appropriate platform credentials. It is categorised as a Write tool in the Infracost 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 infracost_comment? +

Register the Infracost MCP Server MCP server in PolicyLayer and add a rule for infracost_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 Infracost MCP Server. Nothing to install.

What risk level is infracost_comment? +

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

Can I rate-limit infracost_comment? +

Yes. Add a rate_limit block to the infracost_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 infracost_comment completely? +

Set action: deny in the PolicyLayer policy for infracost_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 infracost_comment? +

infracost_comment is provided by the Infracost MCP Server MCP server (phildougherty/infracost_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.