conversations_set_purpose · Slack MCP: Risk & Policy

WHAT IT DOES

What conversations_set_purpose does on Slack

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

WHY IT NEEDS A POLICY

Why conversations_set_purpose needs a policy

This tool modifies conversation metadata (purpose) in Slack, which is a reversible change. It does not delete data (Destructive), execute arbitrary code (Execute), move money (Financial), or merely retrieve information (Read).

From the tool's definition Tool name 'conversations_set_purpose' and description 'Set the purpose for a conversation' indicate this modifies conversation metadata.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

conversations_set_purpose Rate-limited

conversations_set_purpose 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": {
    "conversations_set_purpose": {
      "limits": [
        {
          "counter": "conversations_set_purpose_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 Slack, so you can run agents against it safely.

FAQ

Questions about conversations_set_purpose

What does the conversations_set_purpose tool do? +

Set the purpose for a conversation. It is categorised as a Write tool in the Slack MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on conversations_set_purpose? +

Register the Slack MCP server in PolicyLayer and add a rule for conversations_set_purpose: 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 Slack. Nothing to install.

What risk level is conversations_set_purpose? +

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

Can I rate-limit conversations_set_purpose? +

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

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

conversations_set_purpose is provided by the Slack MCP server (karbassi/slack-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.