AI agents call slack_find_user to retrieve information from Access without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
The tool performs a lookup/search operation (Read category) with no side effects. It queries existing Slack user data and returns information. The severity is low because it retrieves only non-sensitive user metadata (ID, display name, profile info) that is typically not confidential in a Slack workspace context. The confidence is high because the description clearly indicates read-only retrieval behavior.
From the tool's definition Tool description states 'Look up a Slack user by their email address. Returns user ID, display name, and profile info.' This is a query operation that retrieves data without modifying or deleting anything.
Attacks that exploit this kind of access
Look up a Slack user by their email address. Returns user ID, display name, and profile info. Use this when you have an email but need the Slack user ID for sending messages. It is categorised as a Read tool in the Access MCP Server, which means it retrieves data without modifying state.
Register the Access MCP server in PolicyLayer and add a rule for slack_find_user: 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 Access. Nothing to install.
slack_find_user 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_find_user 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_find_user. 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_find_user is provided by the Access MCP server (scottpedia0/access). 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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