I think this space is very untapped. Models are interesting, but I am absolutely obsessed with some things I've been researching/working on for the past few years:

Fractal tool discovery: tool taxonomy where an agent can "drill deeper" to find what specific tool it's looking for. Helps if/when polluting context with a zillion (mostly unnecessary) tools.

Leveraging splay trees: this is my favorite data structure and I think relatively unused in the context of agents/harnesses. A lot of times, recently-used workflows/tool-chains will be used again, so having those at the top of the search hierarchy is an awesome optimization.

Virtual containerized notebooks: models working in sandboxed (WASI) Python notebooks is incredible. Even local models (if given enough time) will usually converge on a good solution. Being able to mount tools/resources/fs is again, imo quite untapped. Some problems here are running native things (thing numpy/pandas) in containers is a nightmare (or impossible).

Anyway, happy to see other folks seriously doing stuff in this space. If anyone wants to collaborate on anything don't hesitate to reach out :) I'm also actively looking for a job or some contract gigs.

Fun times ahead.

What makes it fractal?

It's kind of self-expanding/looping; fractal is just a cute name I like, but it's technically a directed cyclic graph (since you always have/want cycles).

The headline graph is kind of bizarre.

For some reason they're comparing their harness running on Astra xhigh to Codex with Astra max?

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Also worth noting that OpenAI just added support for async tool calling to their harness, which isn't 1:1 with this approach, but is slowly ramping up in being able to provide something similar.

A big part of why Codex uses so many tokens is that it basically hot loops on polling tasks it starts for... absolutely no good reason: https://www.reddit.com/r/codex/comments/1wdlp7q/weve_discove...

I fixed it on my fork of Codex too, also back in Jan/Feb – I keep this patch rebased, for anyone who wants it: https://github.com/tekacs/codex/commit/9ffcf8db9078eae43d411...

It results in token savings similar in scale to those displayed here by Unreal.

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My harness has used a slightly fancier version of the approach that Unreal is using since ~Feb, and... it definitely works excellently, but it's also assuredly smoother with Astra and other recent models that are more aware of async tool calling.

To reduce the codex polling I slapped this into my ~/.codex/config.toml:

  [features.multi_agent_v2]
  enabled = true
  wait_agent_enabled = true
  min_wait_timeout_ms = 10000 # 10s
  default_wait_timeout_ms = 300000 # 5m
  max_wait_timeout_ms = 3600000 # 1h

Seems to do the job and reduce usage; I just ran Astra for ~5 hours (using a goal) and it used the last 30% of my usage. And now they released GPT-6 Sol and Luna (which is basically 5.6 Sol and Luna, but a bit better and also 50% cheaper) ;_;

that's like the worst name you could have picked

Sounds like a trademark issue when Epic ships a wildly popular Unreal Engine

But I don't think you can trademark a generic word like Unreal...

They've trademarked it for quite a few closely-related domains: https://tsdr.uspto.gov/#caseNumber=87709072&caseSearchType=U...

>Computer software, namely, game engine software for video game development and operation; Computer software, namely, software development tools for the creation of computer-generated imagery and graphics for the production of video games; Computer software, namely, software development tools for the creation of computer-generated imagery and graphics for the production of content for virtual worlds and 3D platforms; Computer software, namely, software development tools for the creation of computer-generated imagery and graphics for the production of motion pictures, television shows, videos, 3D animations, 3D simulations, 3D visualizations, virtual reality motion pictures, virtual reality television shows; Computer software, namely, software development tools for the creation of computer-generated imagery and graphics for the production of virtual reality video games; Virtual reality game software; Virtual reality software for creating multimedia content; Augmented reality game software; Augmented reality software for use in mobile devices for integrating electronic data with real world environments for the purposes of entertainment

Those do all seem directly tied to what Unreal Engine does i.e. graphics

Apple? https://en.wikipedia.org/wiki/Apple_Corps_v_Apple_Computer

Unreal is trademarked. This is not in question. And personally I 100% thought this was an agent specifically for dealing with the Unreal Engine, and was interpreting all of that information in that context. Very weird name for a company/product.

Same, I thought this was going to be a plugin for creating content in Unreal engine.

>"But I don't think you can trademark a generic word like Unreal..."

Sure you can, trademarks are contextual. If they were a landscaping business it wouldn't matter. But within the same industry absolutely.

happy to see more harnesses in the Go space, i've had a fun time building https://github.com/ChaseRensberger/wingman

i think the language primitives map well to the natural desire to use these tools across networks and in concurrent workloads.

another Go harness i keep up to date with is: https://github.com/boldsoftware/shelley (exe.dev team)

I think this is what I’ve been waiting for! Live interactions with models are fundamentally asynchronous! This will be great for interactivity.

What a good time for harness design. Just while OpenCode is growing up a bit and focusing on their harness. I’m delighted to see people focusing on good general solid harness design principles.

Someone make an OpenCode API (the best general agent end UI API I know) compatible server for it!

Sucks that I haven’t upgraded my client to V2 yet and I don’t really want to build on an outdated API ...

Edit: It would be cool to get streaming responses :) But I understand (and actually applaud) that the authors seem to have been very focused on the core mechanics.

Also note that this works with the responses API!

I don't really understand how async tool calls translate to token savings

It says that it removes tokens wasted while a model is waiting on synchronous tool calls. What tokens exactly is Pi using when waiting?

I think a running agent periodically checks if a process it started has finished.

Why don't you explain what's different?

Honestly the fact that we're still modeling agent harnesses like chat and strapping them into shell sessions instead of building async actor systems with sandboxed OS functionality access actors is bananas to me. So much easy wins can be had just by building on right abstractions... Hopefully will get enough time to play with this idea soon on my own.

Do you have any examples of this approach?

This feels like it's begging for a lawsuit from Epic.

Epic harness -- unreal agent!

Can I use it with my codex sub?

I think the biggest selling point of a codex sub vs a claude sub is that you can use codex subs in any harness you want.

This is not an Unreal Engine agents? Very disappointed

Mildly disappointed that this has nothing to do with Unreal Engine, the popular game engine.

Yeah, I was hoping it would be something to make it easier for agents to interface with Unreal Engine games.

Unreal 5.8 has a MCP plugin

I was imagining a talking head avatar rendered in Unreal Engine, with lip sync and facial expressions driven by a multimodal LLM that produces the speech.