Search for messages in Slack
AI agents call slack_search_messages 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 performs message search functionality, which is a read-only operation that queries existing data. It does not create, modify, delete, or execute any actions. Even with broad search capabilities, the blast radius of misuse is limited to unauthorized information disclosure rather than data modification or system impact. Classified as Read with low severity.
From the tool's definition Tool name 'slack_search_messages' and description 'Search for messages in Slack' indicate a query operation that retrieves message data without modifying, deleting, or executing actions.
Attacks that exploit this kind of access
Search for messages in Slack. 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_search_messages: 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_search_messages 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_search_messages 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_search_messages. 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_search_messages is provided by the Slack MCP Server MCP server (sdancy10/slack-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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