Fazm vs Simular AI
A voice-first, open-source desktop agent vs an autonomous computer agent from ex-DeepMind researchers. Two approaches to AI on macOS - here's how they compare.
Two philosophies. Very different experiences.
Both Fazm and Simular AI can control your desktop. But they take fundamentally different approaches to how you interact with them and how they see your screen.
Fazm's approach
Voice-first + accessibility API
Voice-first input
Push-to-talk with one keyboard shortcut. Speak naturally and Fazm acts.
Accessibility API
Reads the macOS accessibility tree for instant, precise element targeting. No screenshots needed.
Local screen analysis
Processes your screen locally before anything leaves your machine.
Knowledge graph
Indexes your files and builds persistent context across sessions.
Simular's approach
Text chat + screenshot grounding
Text-only input
Type instructions into a chat interface. No voice control available.
Screenshot-based vision
Captures screenshots and uses vision models to identify UI elements. Agent S2 dropped accessibility trees entirely.
Cloud LLM processing
Screenshots sent to cloud-hosted models (GPT-4, Claude, etc.) for analysis and decision-making.
Neuro-symbolic replay
Records successful workflows and converts them into deterministic, repeatable code.
Feature-by-feature comparison
How Fazm and Simular AI stack up across every dimension.
Talk to your Mac. Don't type at it.
Fazm is built around voice - push-to-talk with one keyboard shortcut. Simular AI requires you to type instructions into a chat interface, adding friction to every interaction.
- Push-to-talk voice input
- Natural language commands
- One keyboard shortcut to activate
- Instant transcription
- Text-only chat input
- No voice control
- Type every instruction
- No hands-free option
Accessibility API vs screenshots
Fazm uses the macOS accessibility API for precise, instant interaction with UI elements. Simular AI relies on screenshot-based visual grounding - taking screenshots and using vision models to identify where to click. The accessibility API is faster, more reliable, and doesn't require sending images to cloud servers.
- macOS accessibility API
- Sub-second element targeting
- Reads full UI structure
- No screenshots needed
- Screenshot-based grounding
- Vision model identifies UI elements
- Depends on visual recognition
- Requires image processing
Your screen stays on your Mac
Fazm processes screen analysis locally before anything leaves your machine. Simular AI captures screenshots of your desktop and sends them to cloud-hosted LLMs for visual grounding and decision-making. If your screen shows sensitive data, that data goes to the cloud.
- Screen analysis runs locally
- Data stays on your Mac
- No screenshots sent to servers
- Privacy by architecture
- Screenshots sent to cloud LLMs
- Requires external model APIs
- Screen data leaves your machine
- Cloud-dependent processing
Fully open vs partially open
Fazm's entire codebase is open source on GitHub - the agent, the UI, everything. Simular open-sources their Agent S research framework, but the actual Simular Desktop product is proprietary and requires a paid subscription for full features.
- Entire project is open source
- Inspect and modify any code
- Community contributions welcome
- No vendor lock-in
- Agent S framework is open source
- Desktop product is proprietary
- Paid subscription required
- Limited community access to product
Knows your files. Understands your workflow.
Fazm indexes your local files and builds a knowledge graph so it understands what you're working on. Simular sees what's on screen and can interact with visible UI elements, but doesn't build a persistent understanding of your workspace.
- Indexes local files
- Builds knowledge graph
- Persistent context across sessions
- Understands your projects
- Sees current screen only
- No local file indexing
- Session-based context
- Task-focused, not workspace-aware
About each product
Simular AI
by Simular (ex-DeepMind)
An autonomous computer agent built by former Google DeepMind researchers. Raised $21.5M Series A led by Felicis, with NVentures (Nvidia) participating. Uses a “neuro-symbolic” approach where the LLM writes code that becomes deterministic and repeatable. Their open-source Agent S framework scores 72.6% on OSWorld with Behavior Best-of-N. The commercial Simular Desktop product offers task recording and replay, screenshot-based visual grounding, and supports both macOS (15+ with Apple Silicon) and Windows. Pricing includes Plus, Pro, and Enterprise tiers.
Fazm
Open source
An AI computer agent for macOS that goes beyond the browser. Controls your mouse, keyboard, browser DOM, and native apps - all triggered by voice. Indexes local files, builds a knowledge graph, and integrates with Google Workspace. Screen analysis runs locally for privacy. Uses the macOS accessibility API for precise, sub-second element targeting rather than screenshot-based vision. The entire project is open source. Free to use with no subscription required.
Accessibility API vs screenshot grounding
The way an agent “sees” your screen determines its speed, accuracy, and privacy. Fazm and Simular take opposite approaches.
Fazm
macOS accessibility API
- Reads the full accessibility tree - knows every element, label, and state
- Sub-second element targeting without vision model inference
- Works reliably even when UI looks different across themes
- No screenshots captured or sent anywhere
- Deterministic element identification by role and label
- Processes screen structure locally on your Mac
Simular AI
Screenshot-based visual grounding
- Agent S2 operates solely on raw screenshots as input
- Uses specialized vision models to identify UI elements
- Earlier Agent S used accessibility trees, but S2 dropped them
- Screenshots sent to cloud LLMs for analysis
- Visual recognition can fail on unusual UI layouts
- Requires cloud round-trip for each screen observation
Simular's Agent S framework achieves impressive benchmark scores, but its screenshot-based approach means your screen data goes to cloud servers for every action. Fazm's accessibility API approach is faster, more private, and doesn't depend on a vision model correctly interpreting pixels.
When to use which
Choose Fazm if you...
- Want voice-first control over your Mac
- Care about privacy - screen data stays local
- Prefer fully open-source software you can inspect
- Need a free tool with no subscription required
- Want fast, accessibility-API-based desktop control
- Need file indexing and persistent workspace context
Choose Simular if you...
- Want to record and replay workflow automations
- Need Windows support today
- Want the neuro-symbolic approach for deterministic tasks
- Are okay with paid subscription plans
- Prefer text-based chat interaction over voice
Ready to try the voice-first approach?
Download Fazm for macOS and see what a voice-first, open-source desktop agent can do. Free forever.