nu

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nu is an experimental and lightweight harness for AI agents.

⚠️ Development has shifted to the Rust implementation for better performance and scalability. Please check the main branch for the latest updates.

It is built as a monorepo:

• packages/nu-core → @mhoshdev/nu-core — core harness
• packages/nu-coding → @mhoshdev/nu-coding — coding capabilities
• packages/nu-cli → @mhoshdev/nu-cli — OpenTUI-based interface

Quick Start

Run from source

git clone https://github.com/mhoshdev/nu
cd nu/packages/nu-cli
bun start

Provider keys

Set at least one environment variable:

Variable	Provider
GEMINI_API_KEY	Google Gemini
OPENROUTER_API_KEY	OpenRouter

Key UX

• Ctrl+P: command palette
• /quit: exit
• /new: clear conversation
• /rewind: restore previous snapshot
• /fork [name]: create snapshot
• !<command>: direct shell execution

Packages

Package	Description
@mhoshdev/nu-cli	TUI interface (user-facing)
@mhoshdev/nu-core	Core harness
@mhoshdev/nu-coding	Coding capabilities

Roadmap

• Harness core
  • LLM connector (Vercel AI SDK, multi-provider streaming)
  • Output parser, tool schema generator
  • File I/O engine (Bun File API, UTF-8 detection)
  • Reasoning loop (Think-Act-Observe-Repeat)
• Safety & guardrails
  • Shell execution with guardrails
  • Conflict checker (hash-based overwrite protection)
  • Path validator, approval flows
• TUI interface
  • OpenTUI-based chat with markdown & streaming
  • Syntax highlighting (Tree-sitter), diff rendering
  • Command palette, settings dialog, language/theme selection
  • Snapshot system (/rewind, /fork) with shadow-git
  • Token usage footer, input history
• Plugin system
  • Everything-as-plugin with built-in ON/OFF
  • Plugin settings persistence API
  • Fault isolation & collision policy
• Integrations
  • LSP client/router/tools (definition, references, diagnostics, rename)
  • MCP bridge (JSON-RPC, server management UI)
  • i18n (pluggable locale, built-in Japanese)
  • Skills (.nu/skills/*.md auto-loaded into system prompt)
• Distribution
  • Multi-provider model switching (Gemini / OpenRouter)
  • Global install (bun add -g @mhoshdev/nu-cli → nu)
• Persistent memory (3-layer: Identity / Playbooks / Project)
• Compaction pipeline (attention matching, summarization)
• Multi-session management
• Rich snapshot timeline UI
• Rust core
• Tauri client

Docs

• docs/architecture.md
• docs/custom-providers.md
• docs/logging-strategy.md

Development

bun install
cp .env.example .env  # Bun auto-loads .env for local development
bun test
cd packages/nu-cli && bun start

Common commands

bun test
bun lint
bun fix
bun run update-models

Plugin controls (debugging)

• NU_BUILTIN_PLUGINS_OFF: comma-separated built-in plugin ids to disable
• NU_BUILTIN_PLUGINS_ORDER: comma-separated built-in plugin ids for preferred load order