The tool descriptions carry their own handling rules — email bodies are treated as untrusted input, and the agent is told not to act on instructions found inside them or forward content to addresses it discovers there. Size expectations to the send limit: five unique recipients a week makes this a personal mailbox for an agent, not a way to send mail on an application's behalf.
A local CLI that bridges your MCP client to the InboxAPI cloud service over stdio. An account with its own address is created automatically on first run, so there is no signup or API key step.
- A mailbox of the agent's own, with whoami reporting the identity and address it is using
- Reading: the most recent email, a paginated list (20 by default, 50 at most), one message by Message-ID or index position, every message in a thread, and a total count
- Search across received mail by sender, subject or date range, with at least one filter required
- Sending: cc, bcc, priority, an HTML body and base64 attachments; replies carry proper In-Reply-To and References headers and keep the thread intact; forwards take an optional note
- Attachments come back as a signed download URL valid for five minutes
- An addressbook that maintains itself — external recipients are added as you send, and it reports how many of the five slots remain; addresses on InboxAPI's own domains never consume one
- Encryption you can switch on for an existing account and rotate later, with already-encrypted messages staying readable
- Soft-delete for a received message, a claim flow for a mailbox on your own custom domain, service announcements, and bug and feature reports routed to the maintainers
- A help tool that returns the onboarding path, the authentication flow and worked examples
Npm install -g @inboxapi/cli@latest, then point your MCP client at the inboxapi binary — running it with no subcommand starts the stdio proxy, and on first run with no saved credentials it creates an account with a generated name. Credentials are written to your system config directory (for example ~/.config/inboxapi/credentials.json) and injected into tool calls for you. Two limits to plan around: an account can send to five unique addresses per week, and the addressbook holds five external contacts by default. Linking your own email address to the account enables recovery and lifts trial restrictions. Prebuilt binaries ship for macOS, Linux and Windows.
One command — npm install -g @inboxapi/cli@latest