AI tool comparison
LM Studio + Locally AI vs Rubber Duck
Which one should you ship with? Here is the side-by-side panel verdict, pricing read, reviewer split, and community vote comparison.
Developer Tools
LM Studio + Locally AI
LM Studio buys the best iOS local LLM app to go cross-device
75%
Panel ship
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Community
Free
Entry
LM Studio, the most popular desktop app for running local large language models, has acquired Locally AI — the leading iOS and iPadOS app for on-device inference on Apple Silicon. Locally AI's creator Adrien Grondin is joining LM Studio full-time to lead cross-device native AI experiences. The acquisition signals LM Studio's ambition to own the full local AI stack: macOS, Windows, Linux, and now iPhone and iPad. Locally AI was notable for its deep Apple Silicon integration, using Core ML and Metal Performance Shaders to run models like Llama 3 and Phi-3 natively on A-series and M-series chips. The app had a dedicated following among privacy-conscious users who wanted a clean iOS interface without compromising their data to cloud services. LM Studio brings a larger model library, server mode, and a more mature MLX/GGUF toolchain. For local AI enthusiasts, this is a consolidation play in a space that was starting to fragment across too many single-platform apps. A unified LM Studio experience across desktop and mobile would be a significant UX improvement. It also sets up an interesting competition with Apple's own on-device AI ambitions in iOS 19.
Developer Tools
Rubber Duck
A second AI model reviews your Copilot agent's plan before it ships code
75%
Panel ship
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Community
Paid
Entry
Rubber Duck is a new capability in the GitHub Copilot CLI agent workflow that introduces cross-model code review. When Copilot's primary agent generates a plan or implementation, Rubber Duck routes that output to a second AI model from a different provider family for an independent review — catching architectural mistakes, edge cases, and logic errors before any code is committed. The name is a nod to rubber duck debugging, but the mechanism is more like adversarial collaboration: the reviewing model has no stake in the primary model's plan and no context about why certain decisions were made. It approaches the output fresh, which is precisely where different models excel — a model that didn't generate a plan is much better at finding its flaws than the model that created it. This is a meaningful shift in how AI-assisted development works. Most AI coding tools use a single model throughout the entire workflow. Rubber Duck introduces model diversity as a quality-control mechanism, acknowledging that no single AI has perfect judgment and that cross-checking is standard practice in human code review for good reason. It's available now as part of GitHub Copilot CLI.
Reviewer scorecard
“This is the right move for LM Studio. The desktop client is already excellent and Locally AI's Core ML integration is the best iOS inference wrapper available. Combining Grondin's Apple-native work with LM Studio's model management and server mode could produce something genuinely special for local AI power users.”
“The insight here is sharp: models are worst at finding their own mistakes. Using a second model as an independent reviewer is the right call, and it mirrors how good human code review actually works. I want to know which model pairs GitHub is using — the quality of the adversarial check will depend heavily on choosing models with genuinely different failure modes.”
“Acquisitions in open-source adjacent tools often mean the indie app loses what made it great. Locally AI was clean and opinionated; LM Studio is powerful but has more surface area. There's real risk the mobile experience gets de-prioritized once the acquisition honeymoon ends.”
“This doubles your inference cost for every agentic operation, and GitHub hasn't published latency numbers. If the cross-model review adds 10-15 seconds to every agent step, it'll be disabled by most developers within a week. Catch rates vs. latency overhead is the key tradeoff and it hasn't been benchmarked publicly yet.”
“The race to own the local AI client layer is just beginning. LM Studio is positioning itself as the VLC of AI — runs everything, everywhere, free. If they nail the cross-device sync story (shared model library, shared chats), they become the default for privacy-first AI.”
“Model ensembling for quality control is the obvious next step in agentic AI workflows, and GitHub shipping it in Copilot normalizes the pattern. In two years, single-model agent pipelines will feel as naive as shipping code without CI. Rubber Duck is the CI layer for agentic code generation.”
“Being able to run the same model on my MacBook and iPhone with the same interface is a genuine quality-of-life win. I use local models for confidential creative writing and the iOS gap has always been frustrating. This closes it.”
“Honestly, I'd love this for writing. Having a second AI with a completely different perspective review a draft before it goes out catches things the primary model is blind to — that's just good editing practice. The name 'Rubber Duck' is perfectly chosen; it captures the spirit of the feature better than any technical description could.”
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