A Read-Only Grok Bot "CFO" Agent Posted a CEO's Bank Balances to the Company Slack

Shane Mac, CEO of XMTP Labs, and his company's Slack workspace

Mac connected a Grok Bot agent to his bank accounts with read-only access for personal finance reports. On October 1, 2026 his bank balances and itemized spending were posted to a company Slack channel colleagues could see; the agent then apologized and offered to delete the message. Mac says the finance agent had no Slack access but a second agent under the same account did, and the two could reach each other's information through a shared environment; he says no prompt injection or outside attack was involved. The account is Mac's own and not independently verified, and Mac is reportedly building an agent permissions product

"Read-only" limited what the agent could do to the bank, not where the data could go. Agents under one account shared an environment, so one agent's data reached another agent's output channel