This record as markdown: /tools/karbassi-slack-mcp/chat-schedule-message.md
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 chat_schedule_message is rated Medium
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
The rule that runs chat_schedule_message safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Slack, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For chat_schedule_message, this is the rule to start with:
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.
The button opens the PolicyLayer dashboard: create your workspace, connect Slack, apply this rule, and every chat_schedule_message call is checked against it from then on.
Questions about chat_schedule_message
chat_schedule_message is a write tool on the Slack MCP server. 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.
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.
chat_schedule_message is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
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.
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.
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.
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