slack_conversations_add_message

Post a message to a channel, private channel, or direct message

SERVERSage MCP SOURCEsagemcp/sagemcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/sagemcp-sagemcp/slack-conversations-add-message.md

WHAT IT DOES

What slack_conversations_add_message does on Sage MCP

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

RISK

Why slack_conversations_add_message is rated Medium

This tool creates new data (messages) in Slack, which is a reversible write operation. While posts are permanent in Slack's logs, they can be edited or deleted by authorized users. The severity is medium because posting messages could be misused to spam channels, spread misinformation, or impersonate users, but it lacks the irreversibility of destructive operations or financial impact.

From the tool's definition Tool description explicitly states 'Post a message to a channel, private channel, or direct message', indicating creation of new message data that modifies Slack conversation state.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs slack_conversations_add_message safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Sage MCP, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For slack_conversations_add_message, this is the rule to start with:

slack_conversations_add_message Rate-limited

slack_conversations_add_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": {
    "slack_conversations_add_message": {
      "limits": [
        {
          "counter": "slack_conversations_add_message_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Sage MCP, apply this rule, and every slack_conversations_add_message call is checked against it from then on.

FAQ

Questions about slack_conversations_add_message

What does the slack_conversations_add_message tool do? +

Post a message to a channel, private channel, or direct message. It is categorised as a Write tool in the Sage MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on slack_conversations_add_message? +

Register the Sage MCP server in PolicyLayer and add a rule for slack_conversations_add_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 Sage MCP. Nothing to install.

What risk level is slack_conversations_add_message? +

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

Can I rate-limit slack_conversations_add_message? +

Yes. Add a rate_limit block to the slack_conversations_add_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 slack_conversations_add_message completely? +

Set action: deny in the PolicyLayer policy for slack_conversations_add_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 slack_conversations_add_message? +

slack_conversations_add_message is provided by the Sage MCP server (sagemcp/sagemcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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