Fantastic

Fantastic is an AI agent kernel unifies humans, models, programs, and files into a single workspace.

Fantastic is a kernel of agents that unifies humans and AIs into a single workspace. A model, a program, a file tree, a shell, a browser canvas, and the human at the keyboard act as agents in one tree. Every interaction uses one batch send primitive, and agents use reflect and docs to describe themselves so AIs can wire the system. It supports AI agents over vLLM, Ollama, OpenAI Responses API, Anthropic Messages API, and Apple on-device models. IO legs include filebridge, execbridge, webws, webrest, wsbridge, relayconnector, and mcpclient. It provides a persistent tree, scheduler, and task table with Unix-style ps and cancel.

Fantastic at a glance

Best for: Software engineer, Researcher
Runs on: macOS, Linux, Web, API, CLI, open source
Pricing: Free
Released: October 2026
Category: AI agent tool
Website: github.com/aisixteen/fantastic

Key features

Unified agent tree where programs, models, files, and users are agents
Single batch send primitive for concurrent tasks
Self-description via reflect and docs for model-driven wiring
Deny-all two-sided call gate for secure agent communication
IO legs for files, processes, browsers, kernels, and MCP servers
Hot-reloadable folder bundles in .fantastic/
Task table with Unix-style ps and cancel

Use it for

Build, run, and engineer systems visually with an AI canvas
Run AI agents over vLLM, Ollama, OpenAI, and Anthropic APIs
Connect remote MCP server tools as verbs
Manage files, edits, streams, and watches securely

Alternatives to Fantastic

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OpenViking — Unifies agent memory, knowledge RAG, and skills into a single directory structure.
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Supermemory — Integrates long-term memory into AI coding agents with a single prompt.
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Beeuni — Agents retain context and improve skills over time through a controlled review process.
Alook — Connects existing local coding agents to team communication channels.
Super Agent Party — A self-hosted, all-in-one AI agent that controls your computer and live streams.
Starnet — Visual agent management with transparent, persistent on-disk logs and state.

All Fantastic alternatives