Osaurus

Own your AI.
Agents, memory, tools, and identity that live on your Mac. Built purely in Swift. Fully offline. Open source.

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Inference is all you need. Everything else can be owned by you.

Models are getting cheaper and more interchangeable by the day. What's irreplaceable is the layer around them -- your context, your memory, your tools, your identity. Others keep that layer on their servers. Osaurus keeps it on your machine.

Osaurus is the AI harness for macOS. It sits between you and any model -- local or cloud -- and provides the continuity that makes AI personal: agents that remember, execute autonomously, run real code, and stay reachable from anywhere. The models are interchangeable. The harness is what compounds.

Works fully offline with local models. Connect to any cloud provider when you want more power. Nothing leaves your Mac unless you choose.

Native Swift on Apple Silicon. No Electron. No compromises. MIT licensed.

Install

brew install --cask osaurus

Or download the latest .dmg from Releases. After installing, launch from Spotlight (⌘ Space → "Osaurus") or the CLI:

osaurus ui       # Open the chat UI
osaurus serve    # Start the server
osaurus status   # Check status

Requires macOS 15.5+ and Apple Silicon.

Agents

Agents are the core of Osaurus. Each one gets its own prompts, memory, and visual theme -- a research assistant, a coding partner, a file organizer, whatever you need. Tools and skills are automatically selected via RAG search based on the task at hand -- no manual configuration needed. Everything else in the harness exists to make agents smarter, faster, and more capable over time.

Agents can also opt into a private local database and a single self-scheduled next run -- see Agent DB & Self-Scheduling. Local storage is plaintext by default (protected by FileVault) with opt-in SQLCipher encryption -- see Storage.

Agent Loop

Every chat is an agent loop. Pick a working folder and the agent gets file, search, and git tools. Toggle the sandbox and it gets shell access in an isolated Linux VM. The model writes a markdown todo list, executes against it, and closes out with a verified summary -- all in the same chat window. See the Agent Loop Guide.

Sandbox

Agents execute code in an isolated Linux VM powered by Apple's Containerization framework. Full dev environment -- shell, Python, Node.js, compilers, package managers -- with zero risk to your Mac.

Each agent gets its own Linux user and home directory. The VM connects back to Osaurus (inference, memory, secrets) via a vsock bridge -- sandboxed but not disconnected. Extend with simple JSON plugin recipes, no Xcode or code signing required.

┌────────────────┐       ┌────────────────────────────┐
│    Osaurus     │       │   Linux VM (Alpine)        │
│                │       │                            │
│  Sandbox Mgr ──┼───────┤→ /workspace  (VirtioFS)    │
│  Host API   ←──┼─vsock─┤→ osaurus-host bridge       │
│                │       │                            │
│                │       │  agent-alice  (Linux user) │
│                │       │  agent-bob    (Linux user) │
└────────────────┘       └────────────────────────────┘

Requires macOS 26+ (Tahoe). See the Sandbox Guide for configuration, built-in tools, and plugin authoring.

Memory

Three layers -- identity, pinned facts, and per-session episodes -- plus a transcript fallback. Agents distill conversations once at session end (not on every turn), score what matters by salience, and surface at most one compact slice per request based on what you're actually asking. A background consolidator decays, merges, and evicts so memory stays sharp instead of bloating. Most turns inject ~800 tokens or less; many inject zero. See the Memory Guide.

Privacy Filter

When you send to a cloud model, an on-device classifier — OpenAI's openai/privacy-filter (Apache-2.0, 1.5B params / 50M active sparse-MoE), served via the MLX conversion mlx-community/openai-privacy-filter-bf16 (~2.8 GB) — detects names, emails, phones, URLs, addresses, dates, account numbers, and free-form secrets, alongside deterministic regex for SSN, credit cards, IBAN, AWS keys, GitHub tokens, and your own custom patterns. Each detection is shown in a review sheet with a scrubbed preview before sending; approved entities are swapped for stable [PERSON_1] / [EMAIL_2] placeholders, and streaming replies are unscrubbed back on the fly so the chat reads naturally. Fail-closed: if the post-scrub scan finds anything that leaked, the send is blocked. Verify wire-level redaction in the Insights panel — it captures the exact bytes the cloud saw. See the Privacy Filter Guide.

Identity

Every participant -- human, agent, device -- gets a secp256k1 cryptographic address. Authority flows from your master key (iCloud Keychain) down to each agent in a verifiable chain of trust. Create portable access keys (osk-v1), scope per-agent, revoke anytime. See Identity docs.

Relay

Expose agents to the internet via secure WebSocket tunnels through agent.osaurus.ai. Unique URL per agent based on its crypto address. No port forwarding, no ngrok, no configuration.

Secure Channel

When two Osaurus agents talk -- across your LAN or across the world through the relay -- the conversation is end-to-end encrypted: a forward-secret X25519 handshake authenticated by each agent's crypto identity, with every request, streamed token, and access key sealed in ChaCha20-Poly1305. The relay becomes a blind pipe that forwards ciphertext it cannot open; a man-in-the-middle cannot complete a handshake; replayed or truncated traffic is detected and refused; and there is no plaintext fallback an attacker can force. Zero configuration -- pairing is all it takes. See the Secure Channel docs.

Subagents (Spawn)

Let a chat delegate a bounded task to another model -- local or remote -- or to one of your saved agents, and get a compact result back without cluttering the conversation. Perfect for offloading research, coding, or analysis to a specialist mid-turn. When the subagent runs on a local model, Osaurus does a single-residency handoff: it unloads your chat model, runs the job, then reloads and continues, so two large models never fight for memory. Off by default, approved on first use, and configured per agent.

Image Generation

Create images on your Mac, fully offline. Install a local image model -- z-image-turbo, FLUX, Qwen-Image, or Ideogram -- and generate from a text prompt with control over size, seed, and negative prompts; hand it a source image to edit instead of starting from scratch. Your chat model can also call the built-in image tool to generate or edit a picture and render it inline in the conversation. Nothing is sent to a server.

Models

The harness is model-agnostic. Swap freely -- your agents, memory, and tools stay intact.

Local

Run Gemma 4, Qwen3.6, GPT-OSS, Llama, and more on Apple Silicon with optimized MLX inference. Osaurus maintains its own optimized model library on Hugging Face with curated quantizations for the best quality-to-size ratio on Apple Silicon. Models stored at ~/MLXModels (override with OSU_MODELS_DIR). Fully private, fully offline.

Liquid Foundation Models

Osaurus supports Liquid AI's LFM family -- on-device models built on a non-transformer architecture optimized for edge deployment. Fast decode, low memory footprint, and strong tool calling out of the box.

Apple Foundation Models

On macOS 26+, use Apple's on-device model as a first-class provider. Pass model: "foundation" in API requests. Tool calling maps through Apple's native interface automatically. Zero inference cost, fully private.

Cloud

Connect to OpenAI, Anthropic, Gemini, xAI/Grok, Venice AI, OpenRouter, Ollama, LM Studio, or Osaurus Router. Osaurus Router is the hosted path — pay-as-you-go with credits and no separate provider account; Osaurus doesn't store your prompt or response content (only the usage metadata needed for billing), and upstream providers process requests under their own policies. Context and memory persist across all providers. See Remote Providers and Osaurus Router.

MCP

Osaurus is a full MCP (Model Context Protocol) server. Give any MCP-compatible client access to your tools with the command-based stdio bridge:

{
  "mcpServers": {
    "osaurus": {
      "command": "osaurus",
      "args": ["mcp"]
    }
  }
}

osaurus mcp starts a stdio MCP server for the client and proxies tool discovery/calls to your local Osaurus HTTP server. Local-only servers can rely on loopback trust. If Server > Network exposure is enabled, add an access key to the client environment:

{
  "mcpServers": {
    "osaurus": {
      "command": "osaurus",
      "args": ["mcp"],
      "env": {
        "OSAURUS_MCP_ACCESS_KEY": "osk-v1..."
      }
    }
  }
}

In the other direction, Osaurus can also act as an MCP client and aggregate tools from URL-based remote MCP providers. One-tap connect to ~25 well-known providers (Linear, Notion, GitHub, Vercel, Supabase, Sentry, Stripe, Cloudflare, ...) with auto OAuth 2.1 + Dynamic Client Registration, or paste an API key. The Remote MCP Providers UI is for HTTP/SSE MCP endpoints; it does not launch third-party command/args stdio providers. See the Remote MCP Providers Guide for details.

Tools & Plugins

osaurus tools install osaurus.browser    # Install from registry
osaurus tools list                       # List installed
osaurus tools create MyPlugin --swift    # Create a plugin
osaurus tools dev com.acme.my-plugin     # Dev with hot reload

20+ native plugins: Mail, Calendar, Vision, macOS Use, XLSX, PPTX, Browser, Music, Git, Filesystem, Search, Fetch, and more. Plugins target the v3 host API surface — register HTTP routes, serve web apps, persist data in SQLite, dispatch agent tasks, and call inference through any model. Older v1/v2 plugins continue to load unchanged. See the Plugin Authoring Guide.

Document attachments keep structure where the file format exposes it: CSV/TSV tables, XLSX workbooks, PPTX decks, PDF page anchors, and rich document sections are parsed through the document adapter registry before they reach the agent.

More

Skills & Methods -- Skills import reusable AI capabilities from GitHub repos or files, compatible with Agent Skills. Full Claude plugins (skills, scheduled agents, slash commands, MCP providers, and CLAUDE.md context) can be imported from any GitHub repo and managed as a single bundle. Methods are learned workflows that agents save and reuse over time. All are automatically selected via RAG search -- no manual configuration needed. See Skills Guide and Claude Plugins.

Automation -- Schedules run recurring tasks in the background. Watchers monitor folders and trigger agents on file changes.

Voice -- On-device transcription via FluidAudio on Apple's Neural Engine. Voice input in chat, VAD mode with wake-word activation, and a global hotkey to transcribe into any app. No audio leaves your Mac. See Voice Input Guide.

Shortcuts, Spotlight & Siri -- Osaurus ships App Intents, so "Ask Osaurus" and "Run Osaurus Agent" are available system-wide the moment you install -- no setup. Ask your active agent and get the reply inline, or kick off a custom agent in the background. See App Intents Guide.

Developer Tools -- Server explorer, MCP tool inspector, inference monitoring, plugin debugging. See Developer Tools Guide. For the inference scheduler, model leases, continuous-batching engine, and feature flags that tune them, see Inference Runtime.

Telemetry

Osaurus collects anonymous, aggregated usage analytics via [Aptabase]