Fetch a Slack message using a message URL.
AI agents call slack_get_message_by_url to retrieve information from Work Integrations MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves message content from Slack by URL. It performs a read-only query without creating, modifying, deleting, or executing any operations. The scope is limited to accessing individual message data. The blast radius is low because misuse would only expose message content already accessible to users with Slack access, not trigger actions or modify data.
From the tool's definition Tool name 'slack_get_message_by_url' and description 'Fetch a Slack message using a message URL' indicate a retrieval operation with no modification or side effects.
Attacks that exploit this kind of access
Fetch a Slack message using a message URL. It is categorised as a Read tool in the Work Integrations MCP MCP Server, which means it retrieves data without modifying state.
Register the Work Integrations MCP server in PolicyLayer and add a rule for slack_get_message_by_url: 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 Work Integrations MCP. Nothing to install.
slack_get_message_by_url 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_message_by_url 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_message_by_url. 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_message_by_url is provided by the Work Integrations MCP server (nazarky/workspace-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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