Local AI text tools have quietly shifted from niche experiment to genuine productivity advantage. Cotypist is a free, open-source macOS application that installs small language models directly on your Mac, delivering real-time text predictions and suggestions across any text field without requiring an internet connection. Developed by coder Tianyu Gu, it uses lightweight Phi-3 models optimized for Apple Silicon chips, making the kind of AI assistance once locked behind subscription services available instantly and privately on your own hardware.
Key Takeaways
- Cotypist runs Phi-3.5-mini models (3.8B parameters) locally on Apple Silicon Macs, delivering instant text suggestions offline.
- Free download via GitHub; requires macOS 13.6+ and roughly 4-8GB RAM depending on model size.
- Installation via Homebrew takes minutes; models auto-update through the app with no subscription required.
- Outpaces Apple’s Writing Tools on iPhone and iPad, which rely on cloud processing and feel slower in real-world use.
- Eliminates privacy concerns and latency inherent to cloud-based AI alternatives like ChatGPT or Claude.
What Makes Local AI Text Tools Superior to Cloud Alternatives
Local AI text tools eliminate the two biggest frustrations with cloud-based writing assistance: latency and privacy exposure. When you type in Cotypist, suggestions appear instantly without waiting for a round trip to a server. The entire process stays on your machine. Your writing never leaves your laptop. No account login. No data collection. No terms of service to read. This architectural difference matters more in practice than benchmark charts suggest. The moment you experience text completion that keeps pace with your typing speed, cloud alternatives feel like stepping backward in time.
Cotypist achieves this by running Microsoft’s Phi-3.5-mini model, a 3.8-billion-parameter language model small enough to fit comfortably in RAM while remaining capable of understanding context and suggesting coherent completions. The model is optimized for Apple Silicon, meaning M1, M2, and M3 MacBook Air and Pro users get the full benefit. Testing on a MacBook Air M3 shows predictions appearing without perceptible lag, even when switching rapidly between applications. Compare that to Apple’s Writing Tools on iPhone and iPad, which feel sluggish and less contextually aware. One user described Apple’s native tool as feeling like a toy next to Cotypist’s local intelligence.
Installing Cotypist: A Four-Step Process
Getting local AI text tools running on your Mac requires no technical background, though you will interact with Terminal. Here is the exact process. First, install Homebrew if you do not already have it. Visit brew.sh or open Terminal and run the installation command provided there. This takes a few minutes and gives you a package manager for macOS applications. Second, install the LLM framework by running `brew install llm` in Terminal. This installs the underlying library that Cotypist depends on.
Third, download Cotypist itself. Visit the GitHub repository linked in the original article, download the .dmg file, and drag the Cotypist application into your Applications folder. This is the standard macOS installation process. Fourth, launch Cotypist, select your preferred model (Phi-3.5-mini-instruct is the recommended starting point), and let it download the model file, which is approximately 2GB in size. Once downloaded, enable the global hotkey—the default is Cmd+Space—so suggestions appear in any application without needing to switch back to Cotypist. The entire process takes roughly 15 minutes from start to functional AI assistance.
How Local AI Text Tools Actually Work in Daily Use
Once installed, Cotypist integrates smoothly into your workflow. Start typing in any application—email, Notes, a text editor, a web form—and suggestions begin appearing. Highlight text or begin a new sentence, and Cotypist predicts what comes next. Accept suggestions by pressing Tab. Dismiss them with Esc. The tool learns which suggestions you accept and which you reject, gradually improving its contextual understanding of your writing style. Unlike traditional autocorrect, which operates at the word level, local AI text tools understand full sentences and can suggest rephrasing, tone adjustments, or structural improvements.
The application menu allows you to switch models for different tasks. Need to write code? Switch to a model optimized for programming syntax. Composing professional email? Select a model tuned for formal language. Customize suggestion length, adjust temperature (how creative versus conservative the AI behaves), or exclude specific applications from receiving suggestions. This flexibility is impossible with cloud-based tools, where the model is fixed and the service provider controls all parameters. You own the experience entirely.
Why Local AI Text Tools Outpace Cloud Competitors
The comparison between Cotypist and alternatives like Apple Writing Tools, Ollama, or cloud services like ChatGPT reveals why local processing matters. Apple Writing Tools on iPhone and iPad rely on cloud servers, introducing latency and requiring an internet connection. More importantly, they feel less intelligent in practice, offering simpler completions that do not understand nuance. Ollama is a free, open-source alternative that supports Phi-3.5 and other models, but it operates primarily through a command-line interface, making it less accessible for everyday users who want system-wide integration. Opera One Browser supports 150 local language models but confines them to the browser, whereas Cotypist works everywhere you type.
Cloud services like ChatGPT and Claude offer more powerful models, but they require internet connectivity, introduce privacy concerns, and charge subscription fees for premium features. Phi-3.5, the model powering Cotypist, benchmarks competitively against much larger models. Microsoft’s Phi-3.5 beats Gemini and rivals GPT-4o-mini on reasoning and math tasks according to official benchmarks. However, real-world testing on a laptop shows less dramatic advantages than benchmark charts suggest. The practical win is not raw capability but rather speed, privacy, and the freedom to run AI assistance without external dependencies or costs.
RAM Requirements and Hardware Compatibility
Cotypist runs on macOS 13.6 and later on Apple Silicon Macs. The hardware requirement is straightforward: Apple Silicon support. This includes M1, M2, M3, and newer chips. Intel-based Macs are not supported because the models are compiled specifically for ARM architecture. RAM usage depends on which model you download. The smallest Phi-3.5-mini configuration uses approximately 4GB of RAM. Larger variants can consume up to 8GB. If you have a MacBook Air M3 with 16GB of RAM, you will have headroom for the application plus several other programs simultaneously. Older M1 MacBook Air models with 8GB of base RAM can still run Cotypist, though you may experience slowdowns if you open multiple memory-intensive applications at once.
The models download automatically through the Cotypist application interface. Once downloaded, they remain on your machine and require no further internet connectivity. Updates to models happen through the app, ensuring you always have access to improvements without manual intervention. This is a significant advantage over cloud tools, where the service provider controls update timing and can change behavior without your consent.
Is Cotypist Truly Superior to Every Alternative?
The claim that Cotypist is infinitely better than all competitors requires qualification. It is superior for everyday writing tasks on Mac where speed and privacy matter most. For users who need latest reasoning capabilities or are willing to sacrifice privacy for maximum power, cloud services remain relevant. The Phi-3.5 model powering Cotypist is genuinely impressive at its size, but benchmarks do not always translate to real-world performance advantages. In laptop testing, the 3.8-billion-parameter version shows less dramatic improvements over GPT-4o-mini than benchmark scores suggest. For coding, writing, and email composition, the difference is meaningful. For complex reasoning or specialized tasks, cloud models still hold advantages.
The real value proposition of local AI text tools is not absolute capability but rather the combination of speed, privacy, and cost. You get instant suggestions, no data transmission, and zero subscription fees. That combination is genuinely difficult to beat, even if the raw intelligence is not maximum possible.
Why You Cannot Go Back Once You Try Cotypist
After using Cotypist for daily writing, cloud-based text assistance feels antiquated. The latency alone is jarring—waiting a half-second for a suggestion to appear is noticeable once you have experienced instantaneous local completion. More significantly, the privacy aspect becomes impossible to ignore. Every sentence you type in a cloud tool is logged, analyzed, and potentially used to train future models. Cotypist breaks that cycle entirely. Your writing stays yours. The experience of using local AI text tools is fundamentally different from cloud alternatives. It feels like having a smart collaborator who understands context, not a generic word-completion system.
Can You Run Multiple Local AI Models on the Same Mac?
Yes, you can download and switch between multiple Phi-3.5 variants or other compatible models through Cotypist. The application menu allows model selection, so you might keep a smaller 3.8-billion-parameter model for speed and a larger variant for more complex writing. Only one model runs at a time, so you choose based on your current task. This flexibility is not available with cloud services, where the provider selects the model and you adapt to it.
What Happens to Cotypist If Your Internet Goes Down?
Cotypist continues functioning normally. The models are stored locally, and all processing happens on your machine. Internet connectivity is required only for the initial download of models and for receiving updates. Once models are downloaded, you have full text suggestion capability indefinitely without a network connection. This makes Cotypist genuinely useful for offline work, travel, or situations where internet is unavailable or unreliable.
Local AI text tools represent a genuine shift in how we think about AI assistance. Cotypist makes that shift accessible to any Mac user willing to spend 15 minutes on installation. The combination of speed, privacy, and cost makes going back to cloud alternatives feel like a step backward. If you write regularly on a Mac, testing Cotypist is worth the minimal setup effort required.
Edited by the All Things Geek team.
Source: Tom's Guide
