chat_schedule_message · Slack MCP: Risk & Policy

WHAT IT DOES

What chat_schedule_message does on Slack

AI agents use chat_schedule_message 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 chat_schedule_message needs a policy

Scheduling a message is a write operation that creates new data in Slack (a scheduled message object) and will cause side effects (message delivery) at a future time. While the description is empty, the name and context of sibling write/create tools justify Write classification.

From the tool's definition Tool name 'chat_schedule_message' indicates scheduling/creating messages in Slack. Sibling tools include 'apps_manifest_create', 'apps_manifest_update', and similar write/create operations, suggesting this server's tools perform state-modifying actions.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

chat_schedule_message Rate-limited

chat_schedule_message 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": {
    "chat_schedule_message": {
      "limits": [
        {
          "counter": "chat_schedule_message_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 chat_schedule_message

What does the chat_schedule_message tool do? +

chat_schedule_message. 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 chat_schedule_message? +

Register the Slack MCP server in PolicyLayer and add a rule for chat_schedule_message: 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 chat_schedule_message? +

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

Can I rate-limit chat_schedule_message? +

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

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

chat_schedule_message 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.