write_comment · Band MCP Server MCP: Risk & Policy

WHAT IT DOES

What write_comment does on Band MCP Server

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

WHY IT NEEDS A POLICY

Why write_comment needs a policy

This tool creates new content (a comment) on a Band post, which is reversible (comments can be removed via the sibling remove_comment tool). It does not execute arbitrary code, delete data, or move money.

From the tool's definition Tool name 'write_comment' and description 'Write a comment to BAND post' explicitly indicate creation of new data (a comment) on an existing post.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

write_comment Rate-limited

write_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": {
    "write_comment": {
      "limits": [
        {
          "counter": "write_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 Band MCP Server, so you can run agents against it safely.

FAQ

Questions about write_comment

What does the write_comment tool do? +

Write a comment to BAND post. It is categorised as a Write tool in the Band 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 write_comment? +

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

What risk level is write_comment? +

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

Can I rate-limit write_comment? +

Yes. Add a rate_limit block to the write_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 write_comment completely? +

Set action: deny in the PolicyLayer policy for write_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 write_comment? +

write_comment is provided by the Band MCP Server MCP server (kanghouchao/band-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.