Softonic’s piece on miHoYo quietly shipping BSide: Olivia Lin lands inside a category that has grown faster than most coverage admits. The “AI desktop companion” used to mean a 1999-era Shimeji or a Microsoft Clippy joke, and through 2024 and 2025 it became a small but real genre: a character or interface that lives on your desktop, watches what you do (with whatever permissions you grant it), and responds with voice, text, or screen-aware actions. miHoYo’s entry is the most polished public release so far. It is not the only one worth installing.
We tested 8 AI desktop companion apps in 2026 across Windows and macOS. The list spans the anime-styled headline products, the open-source projects that started this category, and a few productivity-leaning takes that lean less waifu and more assistant.
What to look for in an AI desktop companion
The right pick depends on what you actually want the companion for.
- Local versus cloud inference — companions that run a local model keep prompts off third-party servers but need a GPU with 8 GB or more to feel responsive.
- Screen awareness — some companions read the active window with OCR or accessibility APIs; others stay sandboxed in their own overlay.
- Voice and audio — high-quality TTS pulls the experience together; thin or robotic TTS breaks it.
- Customisation ceiling — first-party characters versus user-replaceable models, prompt packs, and behaviour scripts.
- System overhead — a desktop companion that pulls 4 GB of memory and a GPU core is a different commitment from one that uses a hundred megabytes.
- Telemetry and account requirements — what gets sent home and what stays on disk.
Quick comparison
| App | Best for | Platforms | Free plan | Standout |
|---|---|---|---|---|
| BSide: Olivia Lin | miHoYo character polish | Windows | Free, with cosmetic shop | The audio and animation production values |
| Shimeji Browser Extension | The lightest possible mascot | Windows, macOS, Linux | Free, fully | Browser-resident, no install |
| ShimejiEE | Classic desktop mascot | Windows, macOS, Linux | Free, open-source | Hundreds of community character packs |
| WaifuLabs Desktop Companion | AI-generated character art | Windows | Freemium | Fresh character every session |
| Ami Avatar | Productivity-focused assistant | Windows, macOS | Free | Calendar and reminder integration |
| Mantissa | Open-source LLM-driven companion | Windows, macOS, Linux | Free, open-source | Pluggable model backend |
| MateChat | Chat-first desktop overlay | Windows, macOS | Freemium | Multiple LLM backends |
| Wallpaper Engine with Companions | Wallpaper + character bundles | Windows | Paid $3.99 base | Steam Workshop catalogue |
The 8 best AI desktop companion apps for desktop
1. BSide: Olivia Lin — best polished headline release
BSide: Olivia Lin is miHoYo’s first desktop companion product, released through the BSide label and built around the same animation, voice, and character work the studio uses for its mobile games. The character lives in a transparent overlay on Windows, reacts to window focus, plays voice lines based on time of day and the active app, and accepts text input for direct conversation. Local-first audio playback keeps the experience smooth on mid-range hardware. The model backend is cloud-hosted by miHoYo, which means prompts leave the machine; the company’s privacy policy covers the relevant disclosures.
Where it falls short: Cloud inference means a network round trip on every reply. Customisation is limited to outfits and cosmetic packs sold through the in-app shop. The product is currently Windows-only. Some character interactions are scripted rather than fully model-driven.
Pricing:
- Free with a cosmetic shop for outfit packs.
Platforms: Windows.
Bottom line: The most polished public release in the category. Pick this if production values matter and you do not need an offline model.
2. Shimeji Browser Extension — best lightweight option
Shimeji Browser Extension revives the original 2000s Shimeji as a Chrome and Firefox extension. Tiny pixel-art characters walk along the edges of browser windows, react to scrolling and tab focus, and stay out of the way. There is no AI behind the scenes — these companions are scripted — but the extension is the lowest-friction way to test whether a desktop character is something you actually want before installing a full AI companion. Memory and CPU use are negligible.
Where it falls short: No AI behaviour. No voice. Browser-only. No system-wide companion behaviour outside the browser window.
Pricing:
- Free.
Platforms: Chrome, Firefox, Edge, Brave (Windows, macOS, Linux).
Bottom line: Pick this if you want to test the genre with zero install commitment.
3. ShimejiEE — best classic desktop mascot
ShimejiEE is the Java-based, fully open-source rewrite of the original Shimeji project. Hundreds of community character packs are available, the desktop integration is solid across Windows, macOS, and Linux, and the character behaviour is fully scriptable through XML. ShimejiEE is the foundation a lot of newer AI companions built on, and it remains the standard reference for the lightweight end of the category.
Where it falls short: Pure scripted behaviour, no AI. Java runtime requirement. Configuration is XML-first, which puts it slightly out of reach for non-technical users. The default character pack is dated.
Pricing:
- Free, open-source.
Platforms: Windows, macOS, Linux.
Bottom line: Pick this if you want a classic mascot with full control over character behaviour.
4. WaifuLabs Desktop Companion — best for fresh character art
WaifuLabs Desktop Companion uses the WaifuLabs generation pipeline to create a fresh character art set for each session, and pairs it with a small LLM-driven conversation layer. The character itself changes from launch to launch unless you save a specific seed, which is either the killer feature or the dealbreaker depending on the player. Voice synthesis runs through a configurable TTS backend that supports both local models and ElevenLabs-style cloud voices.
Where it falls short: The art generation pipeline runs in the cloud by default; local-only mode requires a GPU with 12 GB or more. The conversational layer is thinner than dedicated chatbots. Outfit consistency between sessions is rough.
Pricing:
- Free with cloud-generated art and a usage cap.
- Paid: Unlimited generation and longer conversation history $9.99/month.
Platforms: Windows.
Bottom line: Pick this if you want a different character each launch and you are happy with cloud generation.
5. Ami Avatar — best productivity-focused assistant
Ami Avatar approaches the companion from the productivity side rather than the entertainment side. A small avatar lives in the corner of the screen, surfaces calendar reminders, picks tasks from a connected to-do list, and offers a chat panel that runs against an LLM you configure (OpenAI, Anthropic, or a local Ollama endpoint). The companion stays muted unless prompted, which is the right behaviour for office use. Ami’s calendar and reminder integration is the cleanest in the category.
Where it falls short: Anime-styled defaults still feel like a productivity gloss over a character app rather than a real assistant. Voice TTS is functional but not memorable. Mobile companion is missing.
Pricing:
- Free with the basic local-only experience.
- Paid: Pro tier $4.99/month for cloud sync and team features.
Platforms: Windows, macOS.
Bottom line: Pick this if you want the companion to actually help with the day rather than just react to it.
6. Mantissa — best open-source LLM-driven companion
Mantissa is the open-source project most often recommended on r/LocalLLaMA when the question of “AI desktop companion” comes up. The character runs as a small floating window on Windows, macOS, or Linux, and connects to whatever LLM backend you configure: local llama.cpp, Ollama, LM Studio, an OpenAI-compatible API, or Claude’s API. The character pack is swappable, voice synthesis routes through Piper or Coqui TTS, and the entire stack is auditable. Mantissa is the pick if local inference and full control matter.
Where it falls short: First-run setup is more involved than the headline products. Voice quality depends on the TTS model you choose. The default character is functional, not polished.
Pricing:
- Free, open-source (Apache 2.0).
- No premium tier; project is community-maintained.
Platforms: Windows, macOS, Linux.
Bottom line: Pick this if you want a fully local companion you can audit and customise end-to-end.
7. MateChat — best chat-first overlay
MateChat sits in the chat-first corner of the genre rather than the character-first corner. A persistent overlay window stays on top of other apps, accepts hotkeyed text input, and routes prompts to one of several configured LLM backends. The avatar is a small portrait rather than a full character animation, and the app’s focus is on making the LLM the fastest thing on your desktop. MateChat is the right pick for users who tried a full companion and decided they only really wanted a fast chat overlay.
Where it falls short: Almost no character behaviour. Voice is functional but not the focus. Customisation is limited to portrait packs and hotkeys.
Pricing:
- Free with a usage cap on the cloud backend.
- Paid: Pro $6.99/month, lifetime licence $39.99.
Platforms: Windows, macOS.
Bottom line: Pick this if you want the chat speed of a real overlay without the animated character on top.
8. Wallpaper Engine with character bundles — best community catalogue
Wallpaper Engine is not strictly an AI desktop companion, but the Steam Workshop catalogue is the single largest source of animated character backgrounds and interactive companion-like wallpapers on Windows. Some Workshop submissions wire up basic responsiveness to mouse and keyboard input. None ship a real LLM behind the character, but the variety and the price are unmatched. Pair Wallpaper Engine with a separate LLM overlay like MateChat if you want both the character and the chat.
Where it falls short: No native AI behaviour. Steam-only. Performance overhead on lower-spec GPUs can be high. Workshop quality varies wildly.
Pricing:
- Paid: $3.99 base licence on Steam.
- Workshop content is free.
Platforms: Windows.
Bottom line: Pick this if you want the largest catalogue of animated companion-style wallpapers and you are happy to pair it with a separate chat overlay.
How to pick the right one
Pick BSide: Olivia Lin if you want the most polished public release and you are on Windows.
Pick Shimeji Browser Extension if you only want to test the genre.
Pick ShimejiEE if you want the classic mascot experience with hundreds of community character packs.
Pick WaifuLabs Desktop Companion if you want fresh character art every session and you are happy with cloud generation.
Pick Ami Avatar if you want the companion to plug into your calendar and to-do list and actually help.
Pick Mantissa if you want a fully local LLM behind the character with the entire stack auditable.
Pick MateChat if you mostly want a fast chat overlay and the character is secondary.
Pick Wallpaper Engine with a separate chat overlay if you want the largest catalogue of animated backgrounds.
FAQ
What is an AI desktop companion?
A small character or chat overlay that lives on your desktop, optionally reacts to what you are doing (active window, time of day, calendar events), and accepts text or voice input. Some run a local LLM, others use a cloud model.
Is BSide: Olivia Lin free?
The base product is free on Windows. Cosmetic outfit packs are sold through an in-app shop.
Are there open-source AI desktop companions?
Yes. Mantissa is the most active open-source project in the category. ShimejiEE is the classic open-source mascot and the foundation a lot of newer companions build on.
Do AI desktop companions slow your computer down?
Scripted mascots like Shimeji use very little memory and CPU. Companions that run a local LLM need a GPU with 8 GB or more to feel responsive. Cloud-backed companions add a network round trip on every reply.
Can I run a local LLM behind the companion?
Yes. Mantissa, Ami Avatar, and MateChat all support local LLM backends through Ollama or LM Studio. Cloud-backed companions like BSide: Olivia Lin or WaifuLabs do not currently expose a local-model option.
