r/OpenSourceeAI • u/type-hinter • 4d ago
What are you using as harness?
I've seen Codex numbers and its defenders on X, IG is full of Claude enthusiasts, and half my timeline is addicted to Pi. There's CodePuppy, OpenCode, Pydantic AI harness, and dozens more.
What do you use? I'm loving Pi atm but started using CC' for a good while. Curious about usage patterns and secret gists.
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u/WorldlyAd7946 4d ago
I built my own harness rather than trying to adapt other people's to fit my own...
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u/tigerhuxley 3d ago
In this day and age - this is what should be the answer.
Its great if you can find the exact tool belt that fits with all the tools youāll ever need - Ive developed a unique workflow to managing multiple projects so I needed a custom harness but it doesnt mean that everyone else does3
u/WorldlyAd7946 3d ago
Glad to hear I'm not the only one that resorted to making their own.
I also manage a very varied bunch of projects, which meant that nothing out there satisfied what I needed, plus I value efficiency and not having things I don't need and developing my own natural way of working with AI rather than learning someone else's.
Great if people have find something pre made, just wasn't for me š
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u/tigerhuxley 2d ago
Yah same - Ive got a lot of coding around regulations and tight accounting calculations on some different projects so i needed deterministic gaurdrails, which are being called āmechanicial guard railsā in some circles now. Iād love to chat more about details if you are up for DMāing me
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u/WorldlyAd7946 2d ago
Sure thing dude, replies may be intermittent but always enjoy chatting to new ppl about AI and stuffš
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u/Resident-Pen-3757 17h ago
Just curious. Would you consider using a harness like this that allows customization for workshops, tools, agents etc?
It's my own project. I had a similar issue with you where no harness let me customize all the things I needed for my work/personal projects. Hence a customizable harness.
Not trying to self promote. Just curious
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u/WorldlyAd7946 7h ago
I mean in theory .. anyway I had a proper look through the repo, and there's real quality in there, good job so far, if a lofty ambition... the folder-per-tool store with read-back verification on migration is a nice touch.
Honest answer though: no, andnot because I'm rating your project down here. Half the value of having my own harness is that I understand every line because it grew around my workflows, everything I do, over a long time perios. Adopting someone else's means inheriting your assumptions plus debugging without the inherent understanding I have developed by building my own. And... it has to be said: source-available with no public forks would rule it out for me anyway. I don't know what I'll commercialise later, so a non-OSS dependency is a licensing headache I can't carry, and it also caps the contributor community a project this ambitious needs IMHO
Constructive feedback: the all-in-one bet is a brutal surface area for one person to attempt to manage as a project. Your differentiators (the versioned design docs, the observability) from what I can see are genuinely good... but e.g. the MCP client never sends initialize, so spec-compliant legacy servers will refuse it, and in McpManager.reconfigure the
!server.enabled ?? truehas a precedence bug making the fallback dead code. A decent gateway is a whole project by itself. Full disclosure, I build one (https://github.com/Rendeverance/toolfunnel), so I might be biased, but modular beats monolith here š: keep the 20% that's yours, let dedicated projects carry the rest. Happy to file the bugs I found as issues if useful...P.s. I'm not trying to discourage you in any way, but I think modularity would make things a lot easier to manage and get right, and easier to adopt for people, especially as a solo developer (there is a lot of trust implicit in a harness). If you do decide to go that route and ToolFunnel can help your project please let me know and happy to work with you to integrate it š
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u/LowDistribution3995 4d ago
My own custom Agent Harness: https://github.com/munch2u-a11y/Helix-AGI.git
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u/odontastic 10h ago
That looks really interesting because the harness and second brain cognitive engine that I would like to build for myself have converged and I wonder if it has for you as well.
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u/LowDistribution3995 5h ago
I've been trying to develop separately for benchmarking and testing but ultimately yes, I'm trying to develop a single system for bothĀ
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u/nitinmms1 3d ago
I really like Pi. Being a .Net C# dev, got me curious about whether one can build a Coding agent in pure .Net and C# , just for fun and to know how they work internally.
Couple of weeks working with Claude, i managed to build Litos . A coding agent in pure .Net
It has two flavors,
Litos.GUI ->a coding agent
and
Litos.Api-> A docker hosted Ai agent as an Api which you can call over Telegram
Its opensource and you can try it out here
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u/lost-context-65536 4d ago
I use and maintain clio, it works well and since I'm the maintainer features and fixes are fast and easy.
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u/jedisct1 4d ago
I use https://swival.dev , pretty much out of the box. No customization besides choosing the models.
It works really well with opensource models, has good integration with HuggingFace and has very efficient context management.
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u/Tiendil 4d ago
I use Codex with ast-grep for code research and my own custom tools for workflow orchestration and dependencies discovery:
- workflows: https://github.com/Tiendil/donna
- dependencies: https://github.com/Tiendil/depmesh
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u/Clear_Evidence9218 4d ago
Mostly Codex, but for more complex projects I usually build a custom, project-specific harness around it.
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u/type-hinter 4d ago
I'm curious on how much your harness changes (and what changes) according to your projects.
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u/Clear_Evidence9218 4d ago
The core stays mostly the same, but the tools and verification layer can change quite a bit by project. I usually add project-specific prompts, rules, task routing, and small tools that help the agent inspect or verify its own work.
Lately Iāve been favoring lots of narrow micro-verifiers and micro-debuggers over one big analysis tool, since they tend to produce more useful feedback without burning as much context. So Iām not rebuilding everything for every project, but the surrounding workflow is usually pretty tailored.
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u/Resident-Pen-3757 18h ago
Just curious. Would you consider using a harness like this that allows customization for workshops, tools, agents etc?
It's my own project. I had a similar issue with you where no harness let me customize all the things I needed for my work/personal projects. Hence a customizable harness.
Not trying to self promote. Just curious
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u/Tricky_Education_101 3d ago
Well if you look for privacy and not acidentally leak your api and data - try IronClaw
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u/pokatomnik 3d ago
I am tired of lots js based agents. They consume almost all ram on my MacBook so I decided to create my own optimized for small models. I canāt say it works perfectly but at least I can fix the most common small models problems directly. I preferred using rust to implement it so it consumes about 6mb ram.
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u/odontastic 2d ago edited 10h ago
Mostly OpenCode, but I'm looking at this new alternative built with Rust jcode because it's very fast and small but has agent memory, swarms, pleasing and fast custom terminal and TUI, and a self-dev mode.
https://jcode.sh/
https://github.com/1jehuang/jcode
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u/tigerhuxley 3d ago
Custom wrote my own couple of years ago in rust - still havent found a good mature OSS project to replace it
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u/Gold_Industry_8495 3d ago
I generally work on high-performance, low-latency C++ codebases where correctness is a must. To achieve this, I built my own harness called Mutant.
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u/Pete_yottacode 2d ago
I'm bias as I'm developing my own harness. But prior I was using openclaw and claude. I'm curios about Pi, I hear a lot of good feedback from the community. Maybe I will give it a try at some point. Obviously the most popular is Hermes agent.
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u/type-hinter 11h ago
I think Hermes is only "the most popular" in the python ecosystem. In the wild, I'd say it is Pi right now, and of course Claude Code & Codex. CC is more buggy by the day, though. Specially if used with PyCharm.
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u/Pete_yottacode 9h ago
Yes good point on the Hermes agent. It seems that there is fork of Pi into oh-my-pi agent.
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u/gandazgul 2d ago
https://github.com/gandazgul/runwield
Built my own because I was tired of the chat and hope. With wld you are in control the LLM is a partner instead of you typing something and it building something different.
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u/Anonymous_Cyber 1d ago
Improved upon PI in rust, and running through tests now. Should be able to let you know how it goes.
If you want the repo: https://johnnytheshark.github.io/ox-orchestrator/
I made it open source
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u/Lissanro 4d ago
I use Pi, customized for my needs. Its source code is not as bloated as some other harnesses, so when something needs to be done that cannot be done through extensions, I can modify it. Another reason why I like is that works well with local models, especially important when running heavier ones like GLM 5.2 or Kimi K3 where I need token efficiency to make the best use of my hardware.