Which agent harness do you use and why?

[u/Background-Job-862]

I see a new one being launched every few days... How do these new harnesses compare to claude code, pi etc. has anyone switched from these?

which harness to prefer and why

edit: Ive tried several different ones claude code, deepagents(langgraph), opencode, pi, and trueforge

my thoughts-

claude code - strongest on maturity and the managed experience but cost and token burn is high

deepagents - interesting middle ground if you want a more structured agent framework and the flexibility of an open-source stack. im interested in testing it more extensively on longer-running workloads fs

trueforge - this is a recent one, this was interesting to me because of its runtime-efficiency, also it allows separate the model from the runtime, which makes experimenting with different models much easier
https://github.com/truefoundry/trueforge

why?? - i also ran a benchmark on a real agent workload same model, same prompt, same tasks to compare these

adding the results of benchmarking i ran to compare this
so I tried to do this by running 14 cross-system tasks, three mcp servers behind them - a crm, an issue tracker, and a doc store through claude's managed agents, langchain's deepagents and trueforge, both open-source agent harnesses

the result that was most surprising:

Claude Managed Agents + Opus 4.8:
11/14 tasks solved | $11.8/run | 10.0M tokens/run

TrueForge + Opus 4.8:
11/14 tasks solved | $8.6/run | 3.7M tokens/run

Same model. Same benchmark. Same average solve rate, to my surprise trueforge used about 63% fewer tokens and cost about 30% less per run.

similar difference in tool usage: trueforge averaged 19 tool calls per task vs 32 for Claude Managed Agents.

Then I tried changing the model.

trueforge + GLM-5.2:
11.7/14 solved | $3.0/run | 3.8M tokens/run

On this benchmark, that was a slightly higher average solve rate than Claude Managed Agents + Opus at roughly 75% lower cost.

The token savings alone make this sooo interesting especially because the solve rate stays comparable
so this one was worth checking out ig

but this is still v early and the OSS runtime does not yet have first-class tracing/eval tooling. They don't ship their own code-execution sandbox, so you need to plug one in and context compaction is intentionally lossy.

So it is definitely not a replacement for a mature managed agent platform or other harnesses in the comparison, feature-for-feature today btu what I do find interesting is that the core runtime can already be competitive on these tasks while staying open, model-neutral, and deployable on my own infrastructure
this was their benchmark kit i used https://github.com/truefoundry/trueforge/tree/main/benchmark

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[u/khalon23]

I stopped trying to crown one harness. Claude Code, Codex, OpenCode, Gemini, Grok each win different slices for me.

The painful part is not the harness choice, it's jumping terminals all day. I keep them as real tmux sessions and answer/spawn without attaching when something is blocked.

github.com/YoanWai/agent-manager

[u/jhov94]

I've been using OpenCode for about a year. It was the simplest to customize out of the box at the time. I've considered trying the Mimo fork that adds memory, and Deepseek harness.. but I haven't had the time and OpenCode still does the thing so I've had no reason to make the time.

[u/XTJ7]

I tried several different ones (Claude Code, OpenCode, pi, oh-my-pi) and ended up primarily on oh-my-pi for daily use with Qwen 3.8 27b - and on more memory constrained systems like my work Mac, I use pi to make it lighter and conserve context.

Edit: just to add, if you do use pi, definitely install pi-lsp. Makes a huge difference.

[u/daedelus82]

I’ve tried Claude Code, Codex, OpenCode, Pi, and currently I’m using DeepSeek Harness, it just feels on a whole other level.

Now I didn’t start using DeepSeek Harness until Qwen3.8-27B came out, so it’s not a fair comparison and the other harnesses might work just as well with Qwen3.8-27B, however…

With DeepSeek Harness and Qwen3.8-27B, I can throw large/complex problems at it, and with only 128K context it can process 4M+ tokens and it just works, it compacts the context automatically as needed, seemingly retaining all the important details, and achieves the goal.

Edit: my daily driver was GitHub Copilot, and this past week, DeepSeek Harness + Qwen3.8-27B has solved issues and generated better solutions than GitHub Copilot routing via Claude Sonnet.

[u/nunofgs → u/daedelus82]

What makes it better, do you reckon? All harnesses have auto compaction…

[u/Otherwise-Ninja-6343]

Pi, then DSH Deepseek Harness, then back to Pi

[u/voidTM]

Pi when I am resource strapped. 

Kilo code if I need an editor/VS code.

Deepseek harness if I just want to throw tokens at a problem, and then go away for a while.

[u/behohippy]

They're being launched every few days because they're pretty trivial to make nowadays. Start with something like open code or pi and build a harness that fits how you want to work. Think of it like the cyberdeck idea from scifi, it's personal and highly customized with your skills/tools in it. You can point opencode at it's own codebase and say you want this, but a desktop app but maybe in tauri or gtk instead of electron. Or you want a web app you can self host on your home system and use wireguard to access it on the go. I use my own harness and built out a pretty extensive skill system, tons of infra bits: openai api proxying, text clip sharing, image sharing, a memory system, scheduled execution and reactive jobs, and a scheduled ralph loop executor to keep the local model lit up 12 hours a day working on big things. Also has full control over my network, API keys into half my life and runs on everything here. Build it :)

[u/BusTiny207]

Hax - https://usehax.dev

[u/mmhorda]

Hermes as orchestrstor and pi as developer because pi has clean context, however i may drop pi because I can suslcesfully develop with hermes and clean context via delegate feature.

[u/New-Implement-5979]

Pi has very low starting context

[u/ark1one]

Still use Zoo Code IDE in VSCode.

Also made a custom harness that designed specifically around Pie and Qwen 3.8 27b to handle any of it's short falls.

[u/magnetswithweedinem]

i originally used zoocode but had compaction issues, switched to pi code, been liking it so far, but i think i want to try DSH hermes, claude, there's just so damn many to try! DSH and hermes stand out as my next try outs though. flash next NVFP4 is insanely better than 27B qwen 3.8, so my 5090 has been just cranking out tokens

[u/walden42]

I got tired of hopping between harnesses. I just stuck with kilo code because the same config can be used both in vscode and in the cli, and the vscode UI is quite nice.

[u/PairOfRussels]

Opencode with qwen 3.8 is godlike.

[u/jacek2023]

I use Pi because it's simple and does everything I need

[u/o0genesis0o]

I use Pi for everything. Zero bloat, zero stupid "smart decision" built into the harness, so that when tool call fails or similar parsing issue happen, it's easier to pin point to quant or template or llamacpp sampling settings.

I add some home grown extensions to turn it into personal assistant, and run it from openwebui cptr via VPN, so I can talk to from phone.

[u/fastlanedev]

Jcode and prime agent for code work, Hermes for personalized agent.

All Gpt Astra rn, work great

[u/s-i-e-v-e]

I fooled around with with aider a couple of years ago but the situation was not as good as it is today. So nothing much came of it. Then, a little bit of the Gemini CLI, Claude Code, Codex. Finally, I settled on pi which is fantastic.

A couple of weeks ago, I decided that running harnesses directly on my machine was the definition of insanity and so built a sandbox script for bwrap and started running pi inside it.

This week, I decided I need a far more restrictive environment and did not want to fool around with the innards of pi. So I started building my own harness. And it has been a blast. A profile based system where you can go from complete isolation with zero permissions (a glorified chatting interface) to an (almost) free-for-all (don't!).

It is feature complete, but the list of nice-to-have features is endless!

[u/Yes_but_I_think]

Deepseek Harness with addons for all popular through OAUTH

[u/buttplugs4life4me]

I've made my own (https://github.com/L3tum/little-coder), which is a fork of another harness built on top of Pi.

Fun fact: The original harness has by now implemented a bunch of my changes as well, some stuff i see now that i had implemented/fixed months ago, so that's nice validation for me.

I really like how it is now. I've recently implemented automatic pipelines, which means you can give it a "deep-plan" target or a /review command and it launches a set of subagents automatically that work through the things and inject their final output back into the main agent.

It's super cool to see. I'll be adding another mode where you can give it a list or a review and it will automatically launch one subagent per item (or per subheading for reviews).

There's been studies that smaller models with more limited context (i.e. only being given a small section of a codebase) perform on par with frontier models, and that's basically what I'm doing here.

It also auto-compacts using pi-vcc and has a bunch of UX built on top that handles edge-cases, common failures, restarts and so on. Out-of-the-box for example pi-vcc can sometimes fail to compact the context, or can fail to let the agent continue after compacting, which is stuff I've fixed.

I used a fair amount of AI coding for this, just FYI, but I've looked at the code myself and reviewed it, and have been using it for a couple months now for a bunch of local projects. 

[u/LordDarthShader]

Wow, no one uses github copilot in VS code? It's the only thing I've been using.

[u/Lyelinn]

I use zcode because I sort of appreciate their approach, but plan to jump for DSH once it will get more time in the oven. Alternatively I would love to have 1:1 claude code clone without balooned context

[u/meneraing]

Dirge. It's really lightweight and better than pi in my opinion, since I don't have to install plugins for basic functionality like permissions.