Mails.ai is an email API built specifically for AI agents rather than for applications. Inbound messages arrive as structured events carrying an injection score and a sender reputation value, with optional intent and entity classification, a reputation graph, dedicated IPs and an MCP server.
Scoring inbound mail for prompt injection is the detail that matters, and it shows genuine understanding of the threat model. An agent with access to an inbox is reading text written by anyone who knows the address – which makes email the most exposed injection surface most agent deployments have, and one that generic email APIs do nothing about because they were designed for software that does not follow instructions found in its input.
Making classification opt-in is a sound privacy default, and dedicated IP architecture matters for anything sending at volume. Treat the injection score as a signal rather than a guarantee: it raises the floor, and an agent acting on email still needs its own constraints on what it will do without human confirmation.
