AI agents call experiments_get_by_user to retrieve information from Slack without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves A/B experiment assignment metadata for the current user. There are no side effects, no data modification, no code execution, and no financial implications. It is a straightforward read operation returning configuration or assignment state. The 'undocumented' annotation suggests reduced visibility but does not change the fundamental read-only nature of the operation.
From the tool's definition Tool name 'experiments_get_by_user' and description 'Get A/B experiment assignments for current user' indicate data retrieval with no modification. The verb 'Get' confirms read-only operation.
Attacks that exploit this kind of access
Get A/B experiment assignments for current user (undocumented). It is categorised as a Read tool in the Slack MCP Server, which means it retrieves data without modifying state.
Register the Slack MCP server in PolicyLayer and add a rule for experiments_get_by_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 Slack. Nothing to install.
experiments_get_by_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 experiments_get_by_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 experiments_get_by_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.
experiments_get_by_user is provided by the Slack MCP server (karbassi/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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