Xbt Agent with XMTP Agent SDK

This is a basic XMTP XBT Agent that can be used to send and receive messages on the XMTP network. It uses the XMTP Agent SDK to create a basic agent that can be used to send and receive messages on the XMTP network.

It then hits the ai service to answer to dm and group messages.

What this service does

• Creates an XMTP agent using @xmtp/agent-sdk, with codecs for replies, reactions, group updates, and remote attachments configured.
• Subscribes to incoming messages and filters out non-user content (no content, from self, reactions) using filter helpers.
• Adds a temporary "thinking" reaction via middleware, extracts the text from the message (including reply content), and forwards it to your AI backend endpoint: POST {BACKEND_URL}/api/agent/{AGENT_FID}/ask with the header x-api-secret: {BACKEND_API_KEY}.
• Replies back in the same DM or group with the backend's answer when available.
• Logs agent startup details and gracefully handles shutdown signals.
• Persists the XMTP local database to a file named {XMTP_ENV}-{inboxIdPrefix}.db3. When RAILWAY_VOLUME_MOUNT_PATH is set (for example /data), the DB file is written there to allow persistence via a mounted volume.

Prerequisites

• Node.js 20+
• pnpm

Getting Started

1. Clone the repository
2. Install the dependencies
3. Run the agent

Environment Variables

• BACKEND_URL (required): Base URL of the AI backend (used by src/index.ts).
• BACKEND_API_KEY (required): Shared secret sent as x-api-secret to the backend.
• AGENT_FID (required): Agent FID used to build the /api/agent/{fid}/ask URL.
• XMTP_MNEMONIC (required): 12/24-word mnemonic used to derive the XMTP signer.
• XMTP_ENV (optional): local | dev | production (defaults to production).
• XMTP_DB_ENCRYPTION_KEY (optional): Hex key to encrypt the local DB.
• RAILWAY_VOLUME_MOUNT_PATH (optional): Directory for the DB file (e.g. /data).

Notes:

• The agent currently uses XMTP_MNEMONIC for signing.