Get messages from a channel in chronological order. Use this when: 1) You need the latest conversation flow without specific filters, 2) You want ALL messages including bot/automation messages, 3) You need to browse messages sequentially with pagination. Do NOT use if you have specific search cri...
AI agents call slack_get_channel_history to retrieve information from Slack MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves historical message data from Slack channels without modifying, deleting, or executing operations. It is a pure read operation that queries existing data.
From the tool's definition Tool description explicitly states 'Get messages from a channel' with guidance to retrieve conversation flow and browse messages sequentially. No mutation, deletion, or execution capability is described.
Risk signalsBulk/mass operation — affects multiple targets
Documented attack patterns abuse exactly the kind of access slack_get_channel_history gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Slack MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for slack_get_channel_history:
{
"version": "1",
"default": "deny",
"tools": {
"slack_get_channel_history": {}
}
}slack_get_channel_history is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
Free to start. No card required.
Get messages from a channel in chronological order. Use this when: 1) You need the latest conversation flow without specific filters, 2) You want ALL messages including bot/automation messages, 3) You need to browse messages sequentially with pagination. Do NOT use if you have specific search criteria (user, keywords, dates) - use slack_search_messages instead. It is categorised as a Read tool in the Slack MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Slack MCP Server MCP server in PolicyLayer and add a rule for slack_get_channel_history: 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 MCP Server. Nothing to install.
slack_get_channel_history is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the slack_get_channel_history 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 slack_get_channel_history. 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.
slack_get_channel_history is provided by the Slack MCP Server MCP server (ubie-oss/slack-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 11 Slack MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
11 Slack MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.