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edunteman

Re:Show HN: Rampart on CoreML on Tuesday June 30, 2026 @07:22PM (#48740532)
Nice work! Had to do similar serverside for stripping named entities and ended up burning way too much LLM cash
I hate to be that guy, but you can just choose to do these things. Learn to set SMART goals. Then set just one, so there's no excuses around priorities. Obviously, choose well. Make that goal your life.
Re: on Wednesday March 18, 2026 @01:35AM (#47421899)
I’ve been a big fan of “what’s the thinnest this could be” interpretations of sandboxes. This is a great example of that. On the other end of the spectrum there’s just-bash from the Vercel folks.
Re:Why Go Can't Try on Monday March 02, 2026 @01:02PM (#47221604)
The llm detector in my brain went off too
Your repo was actually a major point of reference! Thank you for open sourcing it. Ironically when I first got into zig I built a similar generator for python bridging which your project reminded me of https://github.com/erik-dunteman/zigpy

Ultimate decision for not using a bindings generator was primarily to deeply understand NAPI.

Exactly, that’d be the intention. For compute-heavy or long running jobs you’d still probably want a dedicated VM like on E2B but for quick stuff, bVisor
Correct, your PATH resolves to your local tools as if it was unprotected bash, but syscalls are filtered/virtualized
Hell yeah, love to hear it! Happy to answer any questions or issues you run into

Show HN: BVisor – An Embedded Bash Sandbox, 2ms Boot, Written in Zig

https://github.com/butter-dot-dev/bVisor

bVisor is an SDK and runtime for safely executing bash commands directly on your host machine. We built it on the belief that "sandbox" doesn't need to mean shipping off to remote sandbox products, or spinning up local VMs / containers. Sometimes, you just want to run that bash command locally.bVisor boots a sandbox from user-space without special permissions, powered by seccomp user notifier....

( Read More... | 9 comments | 10 points | on HN )
The part that most resonates with me is the lingering feeling of “oh but it must be my fault for underspecifying” which blocks the outright belief that models are just still sloppy at certain things
Re:Show HN: Butter – A Behavior Cache for LLMs on Tuesday October 28, 2025 @10:45PM (#45742037)
Good question, I imagine you’d need to set up an ngrok endpoint to tunnel to local LLMs.

In those cases perhaps an open source (maybe even local) version would make more sense. For our hosted version we’d need to charge something, given storage requirements to run such a service, but especially for local models that feels wrong. I’ve been considering open source for this reason.

Re:Show HN: Butter – A Behavior Cache for LLMs on Tuesday October 28, 2025 @10:42PM (#45742020)
Ah yes that makes sense, have heard of those cases too but hadn’t put much thought into it. Thanks for pointing it out!
Re:Show HN: Butter – A Behavior Cache for LLMs on Tuesday October 28, 2025 @10:32PM (#45741949)
I’d love your opinion here!

Right now, we assume first call is correct, and will eagerly take the first match we find while traversing the tree.

One of the worst things that could currently happen is we cache a bad run, and now instead of occasional failures you’re given 100% failures.

A few approaches we’ve considered - maintain a staging tree, and only promote to live if multiple sibling nodes (messages) look similar enough. Decision to promote could be via tempting, regex, fuzzy, semantic, or LLM-judged - add some feedback APIs for a client to score end-to-end runs so that path could develop some reputation

Re:Show HN: Butter – A Behavior Cache for LLMs on Tuesday October 28, 2025 @10:25PM (#45741909)
Very, very common approach!

Wrote more on that here: https://blog.butter.dev/the-messy-world-of-deterministic-age...

Re:Show HN: Butter – A Behavior Cache for LLMs on Tuesday October 28, 2025 @09:02PM (#45741363)
Awesome to hear you’ve done similar. JSON artifacts from runs seem to be a common approach for building this in house, similar to what we did with the muscle mem. Detecting cache misses is a bit hard without seeing what the model sees, part of what inspired this proxy direction.

Thanks for the nice words!

Re:Show HN: Butter – A Behavior Cache for LLMs on Tuesday October 28, 2025 @08:56PM (#45741325)
I feel the same - we’ll use it as long as we can since it’s customer aligned but I wouldn’t be surprised if competitive or COGs costs force us to change in the future.
Re:Show HN: Butter – A Behavior Cache for LLMs on Tuesday October 28, 2025 @08:55PM (#45741315)
It’s bring-your-own-key, so any calls proxied to OpenAI just end up billing directly to your account as normal.

You’d only pay Butter for calls that don’t go to the provider. That’d be a separate billing account with butter.

Re:Show HN: Butter – A Behavior Cache for LLMs on Tuesday October 28, 2025 @08:45PM (#45741256)
I couldn’t see how it wouldn’t be, as it’s a free market opt-in decision to use Butter

Show HN: Butter – A Behavior Cache for LLMs

https://www.butter.dev/

Hi HN! I'm Erik. We built Butter, an LLM proxy that makes agent systems deterministic by caching and replaying responses, so automations behave consistently across runs.- It’s a chat completions compatible endpoint, making it easy to drop into existing agents with a custom base_url- The cache is template-aware, meaning lookups can treat dynamic content (names, addresses, etc.) as variablesYou...

( Read More... | 23 comments | 2 points | on HN )
Re:Show HN: Butter, a muscle memory cache for LLMs on Wednesday October 01, 2025 @06:57PM (#45444613)
I've got a blog on this from the launch of Muscle Mem, which should paint a better picture https://erikdunteman.com/blog/muscle-mem

Computer use agents (as an RPA alternative) is the easiest example to reach to: UIs change but not often, so the "trajectory" of click and key entry tool calls is mostly fixed over time and worth feeding to the agent as a canned trajectory. I discuss the flaws of computer use and RPA in the blog above.

A counterexample is coding agents: it's a deeply user-interractive workflow reading from a codebase that's evolving. So the set of things the model is inferencing on is always different, and trajectories are never repeated.

Hope this helps

Re:Show HN: Butter, a muscle memory cache for LLMs on Wednesday October 01, 2025 @04:09PM (#45442770)
Thanks! For langchain you can repoint your base_url in the client. Autogpt I'm not as familiar with. Closed loop robotics using LLMs may be a stretch for now, especially since vision is a heavy component, but theoretically the patterns baked into small language models running on-device or hosted LLMs at higher level planning loops, could be emulated by a butter cache if observed in high enough volume.
Re:Show HN: Butter, a muscle memory cache for LLMs on Wednesday October 01, 2025 @04:03PM (#45442693)
An interesting alternative product to offer is injecting prompt cache tokens into requests where they could be helpful; not bypassing generations but at least low hanging fruit for cost savings

Show HN: Butter, a muscle memory cache for LLMs

https://docs.butter.dev

Hi HN, Erik here. Today we launch Butter, an OpenAI-compatible API proxy that caches LLM generations and serves them deterministically on revisit.Since April, we’ve been working on this concept of “muscle memory,” or deterministic replay, for agent systems performing automations. You may recall our first post in May, launching a python package called Muscle...

( Read More... | 11 comments | 14 points | on HN )
Re:We reverse-engineered Flash Attention 4 on Saturday September 27, 2025 @07:46PM (#45400346)
I'd argue that understanding disassembled assembly could be considered reverse engineering, which would logically extend to source code unless we draw the line at compilation
Re:Show HN: Muscle-Mem, a behavior cache for AI agents on Thursday May 15, 2025 @04:55PM (#43999253)
Love your sleep time stuff! It's an inspiration for Muscle Mem
Re:Show HN: Muscle-Mem, a behavior cache for AI agents on Thursday May 15, 2025 @02:32PM (#43997893)
Great to see you here :) thanks for the kind words!
Re:Show HN: Muscle-Mem, a behavior cache for AI agents on Thursday May 15, 2025 @02:43AM (#43992451)
totally follows! thanks for sharing, will noodle on it
Re:Show HN: Muscle-Mem, a behavior cache for AI agents on Thursday May 15, 2025 @01:48AM (#43992199)
Definitely, but there's lots of API surface area to figure out first, so will stick strictly to python for now. I can see a future where this ends up with a native storage/query core and with python/js bindings on top.

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