Find a Slack user by their email address. PREFERRED method for resolving users — exact match, no ambiguity. WHEN TO USE: Always use this tool (instead of list_slack_users name search) when you have the user
AI agents call lookup_user_by_email to retrieve information from Apple Shortcuts without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves user information from Slack without modifying, creating, or deleting any data. It is a straightforward read operation that queries an existing resource (user lookup by email) and returns results. The emphasis on 'exact match, no ambiguity' further confirms this is a safe lookup operation with no capability to alter state.
From the tool's definition The tool description explicitly states it 'Find[s] a Slack user by their email address' and is described as the 'PREFERRED method for resolving users', indicating a query/lookup operation with no side effects.
Documented attack patterns abuse exactly the kind of access lookup_user_by_email gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Apple Shortcuts, and nothing reaches the server without passing your rules. This is the rule we recommend for lookup_user_by_email:
{
"version": "1",
"default": "deny",
"tools": {
"lookup_user_by_email": {}
}
}lookup_user_by_email 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.
Find a Slack user by their email address. PREFERRED method for resolving users — exact match, no ambiguity. WHEN TO USE: Always use this tool (instead of list_slack_users name search) when you have the user. It is categorised as a Read tool in the Apple Shortcuts MCP Server, which means it retrieves data without modifying state.
Register the Apple Shortcuts MCP server in PolicyLayer and add a rule for lookup_user_by_email: 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 Apple Shortcuts. Nothing to install.
lookup_user_by_email 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 lookup_user_by_email 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 lookup_user_by_email. 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.
lookup_user_by_email is provided by the Apple Shortcuts MCP server (@mindstone/mcp-server-apple-shortcuts). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Apple Shortcuts, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
423 Apple Shortcuts tools catalogued and risk-classified — across an index of 43,000+ MCP servers.