OpenMausBot is an open-source, local-first desktop application that implements a multi-agent chat interface inspired by Grok Bot, allowing users to run a roster of AI agents—each with distinct personalities, models, cloud computers, and connected apps—on their own hardware via the locally installed claude, codex, and grok CLIs. Built with Electron, React, Vite, and Tailwind CSS, the app embeds a harness server on 127.0.0.1:8799 that owns all agent processes, normalizes provider protocols (stream-JSON, JSON-RPC, ACP) into a canonical SSE event stream, and persists transcripts and keys in ~/.openmausbot. Agents can operate on the user's machine (macOS and Ubuntu Xorg with explicit opt-in; Wayland disabled pending issue #345), an isolated Local VM, or a cloud Linux desktop from Boat.dev, with computer-use actions mediated by a permission broker that surfaces shell commands, file edits, and questions as inline Allow/Deny cards. Over 500 apps (Gmail, Slack, GitHub, Notion, Linear) are integrable via Composio Sessions using OAuth. The architecture separates the UI (port 5199) from the harness (port 8799), communicating via HTTP commands and a single SSE stream. Features include mid-conversation model switching, a decision-model router for auto-assigning messages, voice synthesis via ElevenLabs, Fish Audio, Grok (xAI), macOS built-in, or local Chatterbox, and a trigger system for schedules (5–1,440 min intervals, weekday selection) and webhook/app-event automation (Gmail polled every 15 min; Slack/GitHub push). A stdio MCP server exposes a bounded control plane for external clients like Claude Desktop. Packaged releases exist for macOS (Apple Silicon/Intel, signed/notarized), Windows x64 (unsigned installer), and Ubuntu 24.04 x64 (.deb/AppImage, beta). The CLI tool openmausbot enables headless operation (team apply, run, export) for CI/scripts. Licensed Apache 2.0 (enterprise/ folder source-available separately).